Custom plugin changes not showing

For anyone else with this annoying problem:

deactivated and removed plugin from server, moved the plugin file to a new plugin directory folder with a different name, (same plugin name, same shortcode) activated plugin. Now new code being used.

No idea why WordPress was holding onto the old code, but now I don’t care because my problem is solved. Actually I do care, but I can’t spend any more time on this now that it is “fixed”.