Mod version: 1.16.4-7.6.1.71

After giving or deleting an item stack, inventory slots cannot be interacted with until an additional click has occurred.
This occurs in both survival and creative mode, with only JEI present.

Steps to reproduce (giving):

• Spawn in item stack with give mode
• Click on it (or another stack) to pick it up, it is not picked up
• Click again, it is picked up

Steps to reproduce (deleting):

• Delete item stack by dropping it onto overlay in cheat mode
• Click on another stack in inventory, it is not picked up
• Click again, it is picked up

This issue appears to be resolved in 1.18.
Please let me know if you run into any more issues.

I feel as though this may have been a regression from earlier 1.16 versions but I'm not certain. It's definitely something I can confirm is happening for me, as well as two other people that I happened to randomly poll at the time (KnightMiner & Flanks), with the former saying "I've gotten used to clicking twice when I delete items these days".

Thanks for the report!
The deletion bug is a known issue: #2108
Anything else is likely new, we can treat the "giving" as a separate bug that should be simpler to fix.

Present in any version I've tried on 1.16.5. Currently using jei-1.16.5-7.6.4.87
Tried with no other mods on Forge 36.1.0 and 36.1.13 and it still happens. Doesn't happen to me when spawning an item from JEI (right or left click/inventory or mouse pickup) but it always happens after deleting an item using JEI (dropping it on to the item grid on the right). Affects any inventory; player, chest, furnace and any modded inventory.