I think you're right, I'm seeing the same behaviour here. @Mark2AtSafe could you take a look at this?
So it does look like this is a bug. It's now in the hands of the developers and the reference number for the issue is FMEENGINE-29242
It has a high priority (I don't think I can set it any higher) so I would expect a fix sooner, rather than later; but unfortunately I can't say when that might be.
The best workaround I can see is to use cut/copy/paste instead. If you cut or copy the top row and paste it below then it appears to carry the settings with it. It's only the up/down arrows that are messed up.
Apologies for this. I'll let you know as soon as there is a fix issued.
Looks like this is fixed in FME2019.1 (build 19558 or greater). Our QA team says it works fine, but we'll also welcome feedback from anyone who wants to download the beta and give it a try on their own scenarios.