After a discussion with @bartv I investigated more and discovered that there is indeed a regression.
I think it’s coming from:
https://github.com/discourse/discourse/commit/054fbd7846546ae68a5703d47e1750db1bc34ffd
Basically in this case, scrollOnLoad is undefined:
https://github.com/discourse/discourse/blob/master/app/assets/javascripts/discourse/components/topic-list.js.es6#L71
I suggest the following fix:
https://github.com/discourse/discourse/pull/8661
Can you review next week @markvanlan please?