Following on from the solutions in this question, I've been trying to get simulated media keys working on Ubuntu 18.04 on a Lenovo T480s.
First step was to verify that the command
xdotool key --clearmodifiers XF86AudioPlay and indeed it did.
After attempting to use this new shortcut, the command line version stopped working as well (would display the same symbol).
Eventually something I am doing seems to cause the command line version to work again (haven't been able to figure out what, just seems to happen after doing other tasks for a while) but it will break as soon as I attempt to use one of the defined shortcuts.
Can anyone shed some light what I'm doing here that is causing the keyboard shortcuts to not only not work but to get into an unworkable state?