Ghost Challenge?

I’m curious if anybody else encounters this behavior. I play AI a lot and I often receive a challenge after a match finishes. But many challenges don’t appear to be real challenges at all. They don’t appear in my notifications and there is no way to accept them.

Just an FYI. This continues to happen with GnuGo. Just played the bot tonight. I clicked on the “Home” link and there is this challenge I didn’t send. I click on the X to close it.

Then I click on the tournament trophy, check out the current tourney, and then click on “Home” again. The challenge is back. I play another match with another player and when I click on “Home”, the challenge is back.

Finally, I clicked the X button one more time, hit the refresh button in my browser, and now the challenge is gone for good, regardless of how I navigate the site. I’ve played four bots today and GnuGo is the only one that exhibited this behavior.

EDIT
Just sent @EagleEye a challenge, played a match, and he is reporting that after the match he shows the same type of challenge I’m reporting. On my end, there was no such challenge shown.