Inserting items via a basic logistical transporter to a drawer controller stops when the drawer reaches the cap of 2048 items and upgrades are not considered. It is possible to manually input the items in to the drawer controller or drawer and the upgrades are then considered as usual.

Version used: StorageDrawers-1.15.2-7.0.2.jar

There is currently a fundamental mismatch between the way Mekanism and SD is dealing with slots / storage, see my open issue here: #811 . I also submitted the issue to the Mekanism Git, and they seem to think the issue is with SD. My guess is that this issue is in the same bundle of issues as the general Mekanism issues with SD right now.