I'm finding that the Stack inserters are all capped at 18(the base of 4 with the +12 from the original research). When I click on the stack inserter it only shows 18 in the box for the override, and I'm only allowed to enter a number of 18 or below. If I enter a number bigger than 18, the box turns red and doesn't apply the number. If I put 19 items in a box, the stack inserter moves items twice even tho I have a stack Inserter bonus of much higher than the level 7 original tech(+12 or 18 total).

I did some messing around, and it appears that after you pass the normal level, the number doesn't update automatically in the stack inserter.

That being said, there's not really a ton I can do, other than say just check and uncheck the Override Stack Size Box, it will then update.

I will mention this to the devs.

Update: I have made a forum post under the bugs section. Just have to wait to see if it gets a response.

i figured it was something base game, but had no idea how to be sure what was the issue :)

thanx for checking into this, according to the post from the mod on your forum post it looks like this is a known issue that they don't feel is worth fixing :(

Apparently it will update the next time it moves something. Gotta wait until I get home to test.

I've been playing for hours and all inserters of mine only move 18 at once :/ The bonuses screen says they have a bonus of '273' for me.

Unless some other mod I'm using is changing this somewhere. Here's my mods list: https://pastebin.com/YCLQjkMH and the mod settings: https://pastebin.com/r4sT9gAS

I didn't get a chance to test it, but apparently on the forum post...it's not worth the time to fix. Nothing I can do, it's out of my control, other than to remove the research.

https://forums.factorio.com/viewtopic.php?f=7&t=53505&p=313418#p313418