This issue is present as of the 507.1284 build. There is no problem when playing via the Dream Seeker.
Setting a sound() to repeat doesn't work in the webclient. The sound just plays once, then never repeats.
Numbered Steps to Reproduce Problem:
Load this demo into the webclient and click on the "Sound_Loop_Test" verb to see the bug: http://files.byondhome.com/SilkGames/bugs/ NEStalgiaWebclientBugs_v1_src.zip
Code Snippet (if applicable) to Reproduce Problem:
From the linked demo:
src << sound('music_loop.ogg',repeat=1,channel=0,volume=50)
What I've found on this says it's a Chrome bug. Chrome 44 supposedly doesn't have the issue. I'll leave this open in case any new info pops up though.