I need to rescind this report.
It turns out the customer in question had set the default table access
method to columnar, and in this case, it was the Hydra columnar extension
causing the issue. It turns out that this is a known bug:
https://github.com/hydradatabase/hydra/issues/50
They had thought it was fixed with this PR:
https://github.com/hydradatabase/hydra/pull/138
But that turned out not to be the case. I re-submitted a bug report with a
more thorough writeup to them:
https://github.com/hydradatabase/hydra/issues/267
They seem to think there's basically no way to fix this with the current
extension APIs. If someone here happens to know a workaround, I'm sure they
would be receptive.
Cheers!