It sent emails to both of my accounts. I clicked the links in both emails, and confirmed that I wanted to merge the accounts:
Thank you for confirming ownership of your accounts. The account user134206 will be removed, and all rep and votes will be transferred to account Jeremy Banks as a result of this merge:
Please click OK to confirm.
After I clicked OK, I was redirected to my old profile, but it didn't contain any content from the new profile. The links in the emails are now 404, so they were processed in some capacity, but the merge seems to have failed.
I tried again and it produced the same result.