Sort by Date Updated not working correctly for comments

I noticed that observations that get new comments on them get the updated_at field changed, but they don’t seem to move up in the sort order when sorting by Date Updated.

In this screenshot, the 4th observation has "updated_at":"2020-01-26T13:37:17.901-05:00", while the 5th observation has the more recent "updated_at":"2020-01-27T14:00:45.352-05:00". Based on the timestamp of the comment on the 5th observation, it should actually be the first result in this search.

Maybe updated_at only refers to properties of the observation (date, location, dqa fields, annotations, etc), and comments are excepted?

@kueda @pleary I’ve copied the updated_at value for the first 7 observations in this search. The sixth observation had a comment made half an hour ago and its updated_at value was correctly updated, but it’s not getting sorted to the first position. Do you have any insights?