[tor-relays] new log message: [warn] Unparseable microdescriptor

Get this at my exit relay since yesterday:

# head /tmp/warn.log Oct 23 23:30:17.000 [notice] Tor 0.3.5.3-alpha opening new log file. Oct 23 23:30:33.000 [warn] parse error: internal NUL character. Oct 23 23:30:33.000 [warn] Unparseable microdescriptor Oct 23 23:30:33.000 [warn] parse error: internal NUL character. Oct 23 23:30:33.000 [warn] Unparseable microdescriptor

even with log level "debug" there seems to be no more information. Anything I should worry about?