Connecting account to Google fails (BB-9469)

There's some problem connecting my account to my Google account. It happens repeatedly:

1. I come to BitBucket
2. I click the Google button rather than signing in with my BitBucket id/password and get the page shown in connect1.png.
3. I fill in my BitBucket information and click Connect, and get the Error 500 page shown in connect2.png
4. But I am signed in; if I then go to BitBucket.org, I get connect.3png

Thanks in advance,

T.J. Crowder