When you have an item of the requested quality in storage and then replace an item of differing quality with it, the item is not consumed. This allows transmuting items between quality levels. I noticed this while upgrading mining drills. If there is no item in storage, or if you are placing instead of replacing, everything works fine.

Hey, I am currently away from home this week, but I will try to look at all the problems when I come back :)

Fair enough. I shall continue reporting any bugs I spot.

I really like this mod, by the way. These towers are really good at "repairing" the lack of factory in many places :)

This one has the same cause as the other one (items not reimbursed on replacement), only this one is conditional because it depends on the type of container items were in, and I placed the item BEFORE removing the old one, now it's the other way around (and if the new item cannot be placed the removed item is refunded immediately) so this should no longer happen

This still seems to be happening. I was upgrading a mine to rare quality, and logistics storage had the same number of rare drills before and after (42 in this case). not sure if it was refunding the normal quality drills (I have 2.3K). The other three bugs are fixed though.

I was not able to replicate this (for me the new quality always gets removed from chests) but I added more handling for create_entity in case it returns nil when creating an item, please try in the new version :)

The issue persists, but exclusively with mining drills. even in the previous update, non drill items (labs is where I noticed it) did not have any issue. It seems the rare drills are placed then also put in storage, resulting in one drill being actually infinity drills. I suspect https://mods.factorio.com/mod/more-quality-scaling may be causing this. It replaces entities on construction to give otherwise unsupported quality effects.

aaah yes that explains everything, you cannot really change the attributes which quality improves, so basically all quality mods use separate entities for different quality. This means that when you replace a drill, the MQS mod immediately replaces it in place with a technically different one, my script assumes the build failed (the entity name is different) so it refunds the rare drill item. I think I can make it work by comparing only the quality at the exact position instead of the entity name, will try to do something about it

Please retest with the latest release, I have changed the checking system it should now work

It works! I shall now go qualify my mines. Thanks!