Unfortunately from what I can tell, it seems anytime the game performs badly (visible stuttering despite high FPS, or just low FPS - the former from a second-hand account from a player with a high refresh rate monitor and the latter I’ve experienced on the WebGL build) it becomes liable to swallowing dash inputs.
I really wanted to add an input buffer for dashes to counter this, but for now it seems the only way to avoid this is to play the desktop build with a 60hz display (and also just not letting too many enemies fill the screen).