In 1.8.9 if ReplayMod has Q assigned to Quick Mode, it cannot be used to drop items in normal gameplay.

Tested with MultiMC, Minecraft 1.8.9, Forge-1.8.9-11.15.1.1722 and ReplayMod 1.8.9-2.5.2

(no relevant details in log, just adding for completeness)
2021-02-18-1.log

Basically back-porting of fd7b603 to prefabric era and dealing with any forge shenanigans (the reason it was 1.14+ in the first place) on the way.