abort: HTTP Error 405: Method not allowed

I noticed this started happening with nightly unstable builds of tortoisehg (and tip of Mercurial unstable).

{{{
C:\thg-winbuild>hg.exe push --debug
using https://bitbucket.org/tortoisehg/thg-winbuild\\
http auth: user sborho, password ********
sending between command
pushing to https://sborho:***@bitbucket.org/tortoisehg/thg-winbuild\\
sending capabilities command
capabilities: unbundle=HG10GZ,HG10BZ,HG10UN branchmap lookup changegroupsubset
sending heads command
searching for changes
common changesets up to c7dd88b87844
sending branchmap command
1 changesets found
list of changesets:
84d1e6ddd06cb79f5e43dac05a7527fc158b46b8
sending unbundle command
sending 370 bytes
abort: HTTP Error 405: Method Not Allowed
}}}

If I turn around and use the 1.4 release build, installed as Python source on the same machine, the push succeeds.

{{

{\\ C:\thg-winbuild>hg push --debug\\ using https://bitbucket.org/tortoisehg/thg-winbuild\\ http auth: user sborho, password ********\\ sending between command\\ real URL is https://bitbucket.org/tortoisehg/thg-winbuild/\\ pushing to https://sborho:***@bitbucket.org/tortoisehg/thg-winbuild\\ sending capabilities command\\ capabilities: unbundle=HG10GZ,HG10BZ,HG10UN branchmap lookup changegroupsubset\\ sending heads command\\ searching for changes\\ common changesets up to c7dd88b87844\\ sending branchmap command\\ 1 changesets found\\ list of changesets:\\ 84d1e6ddd06cb79f5e43dac05a7527fc158b46b8\\ sending unbundle command\\ sending 370 bytes\\ http auth: user sborho, password ********\\ adding changesets\\ adding manifests\\ adding file changes\\ added 1 changesets with 1 changes to 1 files\\ bb/acl: sborho is allowed. accepted payload.\\ quota: 171.3 MB in use, 150.0 MB available (114.20% used)\\ }}

}