I've been having this problem for a while, it happens randomly, some games I get it and some I don't. Basically the game doesn't let me use skills anymore when it happens, only auto attack. I use mouse buttons for skills, so I don't know if that's a factor, but I tested the buttons outside of the game when I got the bug and still, I couldn't use skills.
I don't know what the trigger is. One time it happened after dying, in this video it happened after using the upgrader machine. The video doesn't actually show much because I don't have a software to detect mouse clicks, but yeah.
#Skills not working
sleek wyvern
It happened while using Sofia, in no particular part of the map.
somber estuary
you wanna know why beacuse you are using fire wave pure 
it wont let u use any abilities
WORST AUGMENT
hope this helps 
dont worry i have been there too
somber estuary
yea dont use that augment total dog water
sleek wyvern
aiiight 
sleek wyvern
sadly I'm not 
sleek wyvern
thanks! :)
tulip thorn
https://tenor.com/view/mindfreak-prx-paper-rex-paperrex-prx-mf-gif-6103081967576...
second fav player