My media player / TV PC has always operated fine with a cordless Logitech keyboard and mouse combo. As part of this, the space bar was play/pause, as is the default for VLC.
However, the mouse was not a convenient control for the kids or wife, because it requires a surface to operate on. After buying a Minix X8-H Plus media player with an Neo M1 air mouse, I picked up an additional air mouse to run the TV PC. It is way more convenient and includes a built-in play/pause button, which is more intuitive. I plan to replace it with a Mele F10 for consistency with the other systems - the F10 has controls more like a DVD player.
However, after installing the M1 air mouse, the space bar on the keyboard no longer acts as the play/pause for VLC. Only the air mouse play/pause button will work.
I am using version 2 of VLC - I don't know what revision. And it worked fine before. And the keyboard itself works fine in all other respects, including spaces when VLC is not active. So something must be assigning play/pause to the remote button to the exclusion of the space bar.
I don't know why any system would do this. Surely if you have a mouse and a keyboard, you might want to use one or the other, so both play/pause keys should work. Or, if you have two air mice, both should work.
Oddly, if I remote in to the system with Teamviewer, the space bar works as expected. So it must be a hardware issue in the actual PC - maybe between the keyboard and mouse, or mouse and air mouse.
[Update]: Removing the mouse and re-installing the air mouse seems to have resolved the conflict. Both the space bar and air mouse play/pause button now work as expected.
So, if your VLC space bar is suddenly not working as expected, try removing any potentially conflicting input devices. It should be possible to get them all working, but a little creative reinstalling might be in order.