https://github.com/openwebwork/webwork2/commit/09515e6b0205234d55a52ba45f58d4a376699649#diff-0a516cc0aae8a140ec58f347a0a56c40
but I'm not positive so keep an eye on it and report back if it starts to fail again.
It was part of the past answer fix for multiAnswers -- I used the new functions created for that to simplify the procedures in GatewayQuizzes.
https://github.com/openwebwork/webwork2/pull/767
So the fix seems to be a by-product of a general attempt to simplify how past answers were stored by GatewayQuizzes.
Thanks for the report.