For some reason, there are no replay mod buttons for play/stop/pause recording on my UI. The buttons are available on my laptop, but not on my desktop. I've re-downloaded and still have the issue. There don't appear to be any hotkeys for play/pause recording, so without the UI buttons, I can only use auto-recording.

Please attach the latest.log file from the logs folder inside your .minecraft folder.

latest.log

Looks like this might be Optifine's fault. Could you try without it and if that fixes it and you require Optifine, then with a newer or older version of it?

That seems to be the case. Thanks.