I think this is just aesthetic, I don't think there is any cause for concern.
Discussion
The fact that they can do this is a concern.
what is concerning about it? As far as I can tell they just re-arranged the block to look that way. The data in the block is not being manipulated. It's just how they are displaying it.
Or am I missing something?
Check the "health" of the block on mempool space. They picked and chose the tx to include in the block, without caring for the tx fees being paid by valid txs. The actual concerning part is MARA actually does censor tx. They don't mine tx from some black listed addresses...
I see your point. They may have just done it for fun. I don't know enough to have much of an opinion, just an observation