Looks like event.userEditBucket is being set to null, which is not allowed. The field should be omitted if it is not required and should not be set.
Mentioned in SAL (#wikimedia-operations) [2021-04-15T23:31:16Z] <jforrester@deploy1002> Synchronized php-1.37.0-wmf.1/extensions/WikimediaEvents/modules/ext.wikimediaEvents/searchSatisfaction.js: Backport: [[gerrit:679845|searchSatisfaction: Default userEditBucket back to 0 edits (T280294)]] (duration: 00m 57s)
All related patches in Gerrit have been merged. Can this task be resolved (via Add Action... → Change Status in the dropdown menu), or is there more to do in this task? Asking as you are set as task assignee. Thanks in advance!