Rengar's audio cuts out after using his ultimate

Exiting your ultimate, taunt, joke, laugh and player only sounds - quotes (for Rengar), cut out and only reappear after using Thrill of the Hunt again. Reproduced in a custom game.

EDIT - it seems that cancelling your ultimate with an ability - not jumping to something with your ult causes this, as using Thrill of the Hunt again does not 100% remove the issue, only jumping to a target, be it a minion or whatever, does.

EDIT #2 - after a few successes, unable to return joke/taunt/laugh/Rengar quotes, has to do with the ultimate in any case