I've noticed that, whenever I stun a chroma, it seems to make their attacks occur instantly, with the delayed attack animation occurring AFTER it's already hit me. I noticed this while using the new rigadoon line - Virulisks, if stunned, will instantly release poison blobs, giving you no chance whatsoever to block or dodge, as soon as they are stunned. The regular Chromas will hit you with their tongue at the wrong point in its animation too.

I haven't tested it with other monsters yet, but it essentially makes stunning a Chroma an adventure in suicide if you attack from the front.