the framed chest seems to consider the top row of the player's inventory as part of the chest for the purposes of shift clicking. if i have an object in that top row:

shift-clicking tries to move it lower in the player's inventory:

if an object is in the chest, and all of the slots in the player's inventory are field except for the top row, it will refuse to move the item in the chest to the player inventory through shift-clicking

tested in 1.18.1 with framedblocks 4.0.2 and both forge 39.0.8, no other mods that interact with inventory or UIs. also checked forge 39.0.10 just for completeness, same behavior.

(i actually first ran into this a couple weeks ago but i got distracted with other things and kept forgetting to report it)

i love how fast you respond to these.