Am with the Op on the one - Might sound like a small issue, but it would annoy me no end on a shorthaul redeye like the OP's. I've had crew take rest in the cabin before- and they were quiet!

The only time (actually twice) that I had 'noise' issues with the cabin crew was to/from YVR. Didn't say anything the first time, but did (early on) ask the FA if they were YVR based on the return leg, and that they had a reputation in the minds of some for being sub-par for CX crew and that I would have to agree, despite my limited experience. The ISM did come over to apologize, and the rest of the flight was 'quieter'.

Perhaps dykia, but in the future, I would not shy away from politely requesting that the crew keep it down, if it's an issue.