How Do I selectively delete revisions? Revision limit not enforced (possibly a bug)

I have just been clicking around my four year old EE instance (which got recently upgraded from version 2 to 3), and found something quite odd:

Several channel entries are having many more revisions than the limit is supposed to cap at ‘10’ (my current settings). In one case it’s more than a hundred revisions stored and I am not sure how this came about. Perhaps I’ve had this set to a higher number in the past, but I’m wondering why it’s not limiting it to the number of revisions like it’s supposed to.

I’m also using the Structure add-on and have checked if there are any settings that could possibly override the CP settings. Seems to be unrelated to Structure.

I know that I can delete all revisions associated to a whole channel, but I’d rather not do that.

My questions related to this:

How can I make it behave like it’s supposed to? i.e. Limit to 10 revisions.

How can I keep the latest 10 revision entries but discard the older ones?

I can live with this, but it seems non-standard behaviour and eventually could lead to concerns about performance. And also it’s quite strange to have to scroll down all the way just to find the more recent revisions I would like to see. (The fixed sorting lists older ones first).

I’ve also posted this to ee stackexchange here.

My last resort is probably SQL queries, but I don’t feel comfortable about that at all.

Thanks in advance for any pointers or help.