hg pull with deployment keys stopped working

#!bash

$ hg pull --debug
running ssh -C hg@bitbucket.org "hg -R <redacted/> serve --stdio"
sending hello command
sending between command
remote: 145
remote: capabilities: lookup changegroupsubset branchmap pushkey known getbundle unbundlehash batch stream unbundle=HG10GZ,HG10BZ,HG10UN httpheader=1024
remote: 1
pulling from ssh://hg@bitbucket.org/<redacted/>
query 1; heads
sending batch command