[@robin-w Moderator 5 years, 6 months ago]

As I say I don’t plan to change how the default works – you can change that for your site, and yes it does not apply retrospectively

‘I also wanted to ask if there is a way to update that field in forum topics when editing in admin.’
yes just edit the topic.

‘leave a comment’ is part of the comment form, and that is disabled when topics for posts shows. You can add that back on dashboard>settings>discussion>bbPress Topics for Posts Strings>Link text