Spacebar not playing preview in After Effects

I've been having a recurring issue in After Effects 2025 on Windows where pressing the spacebar doesn't start playback—instead, it moves the timeline playhead back by one frame. I've ruled out general system issues since the spacebar works fine in other programs, and it functions normally in After Effects right after launch, but breaks mid-session. I’ve reset all keyboard shortcuts, checked that “Play Current Preview” is correctly bound to the spacebar, and confirmed it’s not misassigned to “Previous Frame.” I also verified that no modifier keys are stuck using an external key tester, and I’m not using any third-party input software like AutoHotKey, Razer Synapse, or keyboard macros. I’ve tried resetting preferences, disabling hardware acceleration, checking input methods, and purging cache. Playback works when triggered with other keys, just not the spacebar after a while. This seems like a bug tied to AE 2025’s preview system or a panel focus issue, but I’d love to hear if others are running into this too or know a reliable fix.