Phantom 1 108 Db, Toslink dropout

[Eric58]

When I connect my Phantom1 to my TV via SPdif/Toslink (left speaker), there is often a dropout of the other speaker (right side) of a few milliseconds to many seconds. Is this a knows issue? It seems like the speakers cannot reach each other.
Both speakers are on the same WiFi network.

I've tried connecting the two speakers with an ethernet cable and then rebooting. That doesn't work at all.