A common mistake I personally make is to make a change, but fail to actually save it. (It’s surprisingly easy, especially when you use something like Sublime or Notepad++.)
If you’re using a hosting service (that is, you’re putting up on the web and testing it from there), it may take a while for the hosting service to clear its cache. (e.g. It regularly takes ten or so minutes for updates to Neocities to take place.)
Make sure you’re overriding the cache when you reload. Ctrl+R and F5 can reload information from the cache. Try Ctrl+F5 and/or Ctrl+Shift+R.
(The reason I didn’t reply to this thread before was that I’d forgotten the exact situation when this occurred and was embarrassed about not being able to answer the questions. LOL. This time, it happened locally while testing my game with the python simplehttpserver in Opera (on Ubuntu). I think the last time it happened was either locally or off my herbaloutfitters.com server.
I’ll keep this thread updated with times I experience it again.)