Tor's dormant mode breaks bridgestrap

I just took a look at bridgestrap's metrics and practically all bridges are labelled as offline. Turns out that tor went to sleep a while ago:

[...]
Dec 09 18:58:47.000 [notice] Heartbeat: Tor's uptime is 1 day 0:00 hours, with 0 circuits open. I've sent 5.04 MB and received 18.10 MB. I've received 0 connections on IPv4 and 0 on IPv6. I've made 1935 connections with IPv4 and 2 with IPv6.
Dec 09 18:58:47.000 [notice] While bootstrapping, fetched this many bytes: 5221 (server descriptor fetch); 554212 (consensus network-status fetch); 13117 (authority cert fetch); 2535601 (microdescriptor fetch)
Dec 09 18:58:47.000 [notice] While not bootstrapping, fetched this many bytes: 2986402 (server descriptor fetch); 3599830 (consensus network-status fetch)
Dec 09 18:58:47.000 [notice] Average packaged cell fullness: 43.974%. TLS write overhead: 17%
Dec 09 18:58:48.000 [notice] No user activity in a long time: becoming dormant.
Dec 09 19:38:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 09 19:38:14.000 [notice] Dropping existing bridge descriptor for REDACTED
Dec 09 20:58:47.000 [notice] Tor has been idle for 3600 seconds; assuming established circuits no longer work.
Dec 09 21:08:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 09 22:08:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 09 22:09:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 09 22:10:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 09 23:08:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 09 23:38:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 09 23:39:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 10 00:38:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
Dec 10 00:58:47.000 [notice] Heartbeat: Tor's uptime is 1 day 0:03 hours, with 0 circuits open. I've sent 5.04 MB and received 18.10 MB. I've received 0 connections on IPv4 and 0 on IPv6. I've made 1935 connections with IPv4 and 2 with IPv6.
Dec 10 00:58:47.000 [notice] While bootstrapping, fetched this many bytes: 5221 (server descriptor fetch); 554212 (consensus network-status fetch); 13117 (authority cert fetch); 2535601 (microdescriptor fetch)
Dec 10 00:58:47.000 [notice] While not bootstrapping, fetched this many bytes: 2986402 (server descriptor fetch); 3599830 (consensus network-status fetch)
Dec 10 00:58:47.000 [notice] Average packaged cell fullness: 43.974%. TLS write overhead: 17%
Dec 10 01:08:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.
[...]
Dec 10 03:21:14.000 [notice] Tor 0.4.6.0-alpha-dev (git-3c1d58870cee7e56) opening log file.