Whenever a chest is placed for an existing key, the filter for each slot in the inventory is forced to only accept normal quality instead of whatever quality it was set it, and this also forcibly down-converts the quality of any items already in those slots. This is obviously problematic for builds relying on specific ingredient qualities at various steps. This also removes filters on slots if you have different slots set to different qualities of the same item. ex. if you have 3 slots set to uncommon, rare, and epic of an item, when you place a chest, only one of those 3 slots will be filtered (the other two will be unfiltered and red), that slot will be set to normal quality of the item, and any items that were in any of the 3 slots will have been forcibly down-converted to normal quality.

Edit: placing a chest with an existing key also force-resets the lock (red highlight) on all filtered slots in the inventory, rather than respecting the current slot lock setup.

Edit 2: this also happens when attempting to paste the settings of a chest using shift-right-click -> shift-left-click, making it extremely onerous to set up chests to transfer items above normal quality.

I know, quality is not yet implemented, You are the first to ask.
I don't play with quality and I only noticed this 3 days ago when I played Maraxis ;-)

The actual reason for the behavior is that the dialog does not know “any” You can asks Wube why. ;-)

but you can set the filters yourself at any time (as in waggons, with middle click)
and you can copy and and paste the chests, because this is a factorio feature.

but I'm working on it, so that it can be set up directly at the time of selection.

Ya, but the quality filter gets reset if I copy/paste the chest (using ctrl-C -> ctrl-V), and at least in one attempt, it also appeared to reset when I used the shift-right-click -> shift-left-click method of pasting the chest settings (rather than ctrl-C -> ctrl-V to paste the chest itself). That's the bug that's the issue. If I make one chest, set the filters on it to certain quality levels, place some qualitied items in those filtered slots, and then ctrl-C -> ctrl-V the chest, the filter in each of those slots is reset to the normal quality of that item, and any items that were in those filtered slots are also forcibly down-converted to normal quality. THAT is the primary bug that caused me to make the post (and ya, also on Maraxsis, I'd rather use chests than wonky submarine-spidertrons to transfer stuff between the ocean floor and the trench surfaces).

Also, the middle click method does work for slots, but it requires you to clear the filter in that slot first. If you have ANY inserters trying to push into that specific chest ID, the now-cleared slot is instantly filled with an item, which then prevents setting a filter in that slot. If you use the red X to block the slots, you have to first unset any red slot locking, which again, makes all those slots available for inserters to shove into, which is annoying, but can at least let you change the filter in the now-red-locked slot in peace, even if an inserter is trying to push into the chest. Also, which slots are red-X-locked is reset any time that chest is pasted.

Anyway, to be very clear on how to reproduce the bug:

1) Build a chest of any of the 4 types.
2) Set a filter on the chest, in the right-side menu the mod adds, so the chest is given an ID. Doesn't matter what the filter is, as long as it has an assigned numeric ID.
3) Use middle-click in the actual inventory section of the chest on the filtered slot to remove the filter you added in the mod pane (but retain the chest key assignment).
4) Use middle-click again on that slot, and this time set the filter to an item with any quality setting except = Normal. All other settings, including other specific qualities, inequalities based on quality level, and the rainbow "any quality" option are all effected by the bug.
5) Place some items of non-normal quality, which match the filter you set in #4, into the slot.
6) Close the chest UI, then copy-paste the chest using Ctrl-C -> Ctrl-V onto another empty tile of land nearby.
7) Open either chest, the new or the old one. Observe that the filter you set in #4 is now set to = Normal for that item, and all of the items you placed in that slot in #5, which were above normal quality, are now normal-quality items.

In image form: https://imgur.com/a/B2LTBkB

In place of #6, I've just confirmed that copy-pasting settings between already built chests, using shift-right-click -> shift-left-click, causes the exact same issue. Exact same steps as above, except instead of 6, build a new chest of the same type normal by placing. This chest will not have a key ID or filters assigned. Shift-right-click the original chest. Note that the item is still qualitied. Shift-left-click the new chest to assign it the same key ID. Note that the item has been forced to normal quality and the slot filter reset to = Normal.

Edit: also, as an unrelated bug, the Maraxsis trench and Maraxsis sea floor are not considered "part of the same planet" for the purposes of the Global or Surface chests. The only way to transfer items between them is using the Universe chest.

thanks for the detailed report

I tried:
ctrl-C -> ctrl-V WORKS definitively copies the filter, this is a factorio feature.
shift-right-click -> shift-left-click WORKS too, it is a factorio feature.

but one point I've found: copy WITH items seem to reset the ITEMS to normal. NOT the filter. that is weird.
Alt overlay shows only the content, not the filter

filling the chest during configuration: annoying yes, but I cannot prevent it, without disabling also the UI

the Maraxsis trench and Maraxsis sea floor are not considered "part of the same planet"

i'll have to have a closer look, i haven't played that far yet. you need glass for the dome and i haven't found enough.

Oh, mollusk shells (they're marked as yellowish/tan on the map). They contain glass directly.

https://imgur.com/a/3QuvzfX

I know, but i only found 120 glass. LOL OK i have to look for an even larger radius

regarding the bug , i'll finish the current features first, and then I'll see.
if i do everything at once, there might be more errors than before.

pls try v 3.2 and create a new thread for issues

try the new UI in uppcomming v3.3

Will do, the new quality selection seems to be working (and it defaulting the a red-x "filter" for unused slots instead of no filter is REALLY handy, incidentally), but I've yet to actually dig into quality in my new Gleba-start playthrough yet anyway.

The 3.3 is not yet in the portal
3.2 was only the first attempt ;-)

Oooo, that looks shiny