On two DELL keyboards I've tried SHIFT adds a space so entering COMMAND( ) becomes COMMAND ( ) and results in a syntax error. Anyone else experiencing this ? Thanks.

Me too. I made a new post about this before reading yours. It only does it to me in the console. It does it with alt and some other keys too. I don't think it's a space because the error is " at char(0.03somthing)".

What district are you using?

Same here -- console has the bug,(shift, alt, ...), editor appears to be fine.

Same issue as reported there: https://www.lexaloffle.com/bbs/?tid=3344 (don't know which was the first post to be honest, just it's better to link them)

And it's not distro dependent as the error exist on both the statis and dynamic version of Pico8 for the Pi
It's not only shift, but all the modifier key and arrow key too, in fact I thing that all the key which does not produce a letter are impacted in the editor mode.

I wonder how it behave on a x86 linux (I can't test right now)