Assertion failure in scale_active_circuits

Relay 855BC2DABE24C861CD887DB9B2E950424B49FC34 crashed with the following log entries:

Feb 20 14:33:40.000 [err] tor_assertion_failed_(): Bug: ../src/or/circuitmux_ewma.c:711: scale_active_circuits: Assertion e->last_adjusted_tick == pol->active_circuit_pqueue_last_recalibrated failed; aborting. (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug: Assertion e->last_adjusted_tick == pol->active_circuit_pqueue_last_recalibrated failed in scale_active_circuits at ../src/or/circuitmux_ewma.c:711. Stack trace: (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(log_backtrace+0x42) [0x7f4b7ab65fb2] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(tor_assertion_failed_+0x9f) [0x7f4b7ab80b3f] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(+0xe74b2) [0x7f4b7aac74b2] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(circuitmux_notify_xmit_cells+0xdb) [0x7f4b7aac5a7b] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(channel_flush_from_first_active_circuit+0x269) [0x7f4b7aa5b7d9] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(channel_flush_some_cells+0xe4) [0x7f4b7aaaf8d4] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(+0xbd369) [0x7f4b7aa9d369] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(+0xbb2a2) [0x7f4b7aa9b2a2] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5(event_base_loop+0x414) [0x7f4b7a0ee254] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(do_main_loop+0x255) [0x7f4b7aa35d75] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(tor_main+0x1e75) [0x7f4b7aa397d5] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(main+0x19) [0x7f4b7aa31539] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd) [0x7f4b79103ead] (on Tor 0.3.2.9 )
Feb 20 14:33:40.000 [err] Bug:     /usr/bin/tor(+0x51589) [0x7f4b7aa31589] (on Tor 0.3.2.9 )

Relay runs on Debian wheezy. uname -a: Linux 3.2.0-5-amd64 #1 SMP Debian 3.2.96-3 x86_64 GNU/Linux

Uptime before the crash was 23 days. Memory and CPU usage was normal:

Feb 20 12:55:12.000 [notice] Heartbeat: Tor's uptime is 23 days 17:59 hours, with 30352 circuits open. I've sent 20574.36 GB and received 20125.28 GB.

Trac:
Username: Logforme