Add Application Link not using context path

After upgrading to Atlassian Bitbucket v5.1.0 application links stopped working.

If deleted and a new one is added, the operation times out, and the error log says the manifest is not found. However, the path included in the log is missing the context path prefix.

All other functionality works as expected, other than the application links.

A manual curl request suceeds (https://frottage/bitbucket/rest/applinks/1.0/manifest)

base URL
https://frottage/bitbucket

bitbucket.properties
server.port=7990
server.secure=true
server.scheme=https
server.proxy-name=frottage
server.proxy-port=443
server.context-path=/bitbucket

error log
2017-06-22 19:48:38,363 ERROR [http-nio-7990-exec-7] bob @13C46N1x17187x423x1 x5rkk6 172.28.0.174,127.0.0.1 "GET /rest/applinks/3.0/applicationlink
Form/manifest.json HTTP/1.0" c.a.a.c.r.u.CreateApplicationLinkUIResource Null manifest retrieved