Minecraft Version

1.16.5

Forge Version

36.2.35

Mantle Version

1.6.157

Tinkers' Construct Version

3.3.4.335

Describe your issue

Get yourself any pants with Pockets from tinker's construct mod
Put 1 item of any kind in the pants
Close and reopen pants ui
Shift click 32 items into pants
Close and reopen and the pants have 1 item instead of 33

p.s. i know this bug fixed in 1.18.2.

Crash Report

No response

Other mods

with and without mods

Tried reproducing with just Tinkers?

Yes

Performance Enchancers

Optifine

Searched for known issues?

Searched closed issues

I know that the bug has been fixed in newer versions. I'll just leave this post as a reminder that the bug still exists in this version.
Here is a link to the original post: #5009

Well as you said this bug has been fixed in newer versions. 1.16 is no longer supported however. And is missing quite a lot of features vs 1.18.