Huh, I don't see why it wouldn't give you the medal even though you've achieved the most possible maximum combo on the map. The green text in the score you linked indicates such that. . .
The only thing I can think of other than the medal being bugged for convert maps (which probably isn't the case here bc that would be a bit silly if so, but anything is possible tbh) is that the droplets
could count towards this if they're missed as they are shown to be included in the synopsis of the play:
but as someone who's played catch — the droplets really only count towards the accuracy of the play, so they shouldn't interfere with that iirc
This might seem a bit counter-intuitive, but I would try playing a short 3 or 4 star catch map and FC the map without catching some of the droplets and then again with all the droplets to see if that rewards you the medal at all. Hold off on escape keying from the results screen once you do to see if anything pops up as most medals pop up on the screen shortly after their requirements are met. No worries if you accidentally have a habit of doing this tho as the website is usually good about telling you if you have unlocked any new medals through the notification bell in the top right screen corner of the screen — so be sure to check that as well for anything new ^^^^
If you need a map, here's a new recently ranked catch map you can attempt this on if you need something that's quick to pass and test this out on:
beatmapsets/2054394#fruits/4301618 (every diff up from "RUSTYY'S PLATTER" is above 3 stars, so no need to worry about doing that specific difficulty if you're not comfortable with how it's mapped and all ^^^^)