So this has happened three times in the last week already and I wanted to see who else has had this problem.

Randomly, when I tap the power button no menu is displayed. This should be the menu that includes options like screen lock, offline mode, end current task, and shutdown.

The power button still works as double tapping it does still lock the screen, with a subsequent single tap bringing up the swipe to unlock screen. But I get no menu.

The menu has always returned after a reboot (I'm rebooting it from the command line in these cases, obviously), but like I said I've had to do this three times this week already.

Anyone else had this problem?

Not me. I did have a problem once where the symbols menu wouldn't pop up, but a reboot fixed it.

Yep - I have been having this exact problem. Happening a lot! It only seems to have been since I added the reboot option to the menu, so when I can be bothered I'll undo the changes and see if that's the problem. It's the only thing I've messaed with for a while!