Minecraft 1.16.5 Forge 36.2.35 Forgery 3.3.7
Most control keys stop working when gui opening, for example, if you open your inventory, pressing shift will not make you sneak. But key of crawling(I set it to alt) still working, it means pressing alt can make you crawl even when you open gui.
Only include inventory gui, exclude crafting table, chest...

Are you running any other mods? as i'm not getting the issue holding the crawl key while opening inventory makes me stand again

I tested again with only forgery. The problem still exist.
I means, you can crawl while opening inventory, this is a problem. Because if you are holding shift, opening inventory will make you stand up and stop sneaking, so opening inventory should make you stand up and stop crawling and you should not crawl until you close inventory.

ah i see, i missread the issue to mean "you wont un-crawl when opening inventories" not that "you can crawl while having an inventory open"

Are you running any other mods?
as i'm not getting the issue holding the crawl key while opening inventory makes me stand again

ah i see, i missread the issue to mean "you wont un-crawl when opening inventories" not that "you can crawl while having an inventory open"

yes yes