I confirm the bug of the Super Resolution algoritm with Fujifilm S5pro RAF files.
Here an example:
Original image: RAF 4256x2848
Enlarged: DNG: 11907x3984
Bugs should be reported at https://feedback.photoshop.com/topics/lightroom-classic/5f5f2093785c1f1e6cc40872 They'll be picked up by Adobe QE et al whereas you're just talking to customers like yourself in this forum
Thanks for both the link: I confirm tha the bug is present on both version Lrc and Lr so the problem is in the algorithm of the Super Resolution not only in Lr or Lrc (or Cr).