tor connected to bwauth produces lots of pathbias_count_use_attempt BUG messages

I'm setting up a new bwauth currently. I'm seeing many (~1000 / hour) BUG messages in its logfile:

[notice] Tor 0.2.4.20 (git-0d50b03673670de6) opening new log file. [notice] pathbias_count_use_attempt(): Bug: Used circuit is in strange path state new. Circuit is a General-purpose client currently open.

The config for the tor process (it is a relay to evade static throttling):

SocksPort 9110
ControlPort 9111
Log notice file ./data/tor/tor.log
DataDirectory ./data/tor
PidFile ./data/tor/tor.pid
CookieAuthentication 1

Nickname gabelmoobwscan

RelayBandwidthRate 20480
RelayBandwidthBurst 20480

OrPort 9999

ContactInfo Sebastian <tor@sebastianhahn.net>

ExitPolicy reject *:*