I should say -- these logs are under 2.6.0, but the same bug was happening under 2.8.0. I downgraded to see if the bug would go away. I am upgrading to 2.8.0 again now, and if/when the bug appears again I will post more backtraces.

Follow-up: just got the same freeze on 2.8.0. Backtraces attached, they look the same. 2.8.0 backtraces