Can't update core on Debian Stretch

snap refresh fails on Debian.

alan@debian-stretch-amd64:~$ snap version
snap 2.23.1
snapd 2.23.1
series 16
debian 9
kernel 4.9.0-1-amd64

alan@debian-stretch-amd64:~$ snap change 7
Status Spawn Ready Summary
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:47Z Download snap "core" (1441) from channel "stable"
Done 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Fetch and check assertions for snap "core" (1441)
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Mount snap "core" (1441)
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Stop snap "core" services
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Remove aliases for snap "core"
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Make current revision for snap "core" unavailable
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Copy snap "core" data
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Setup snap "core" (1441) security profiles
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Make snap "core" (1441) available to the system
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Set automatic aliases for snap "core"
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Setup snap "core" aliases
Undone 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Start snap "core" (1441) services
Done 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Clean up "core" (1441) install
Error 2017-03-13T18:06:52Z 2017-03-27T15:19:42Z Run configure hook of "core" snap if present

......................................................................
Make snap "core" (1441) available to the system

2017-03-27T16:09:41+01:00 INFO Requested daemon restart.

......................................................................
Run configure hook of "core" snap if present

2017-03-27T16:19:42+01:00 ERROR run hook "configure": hook "configure" aborted

alan@debian-stretch-amd64:~$