[1.0.2.8] Repair derelict ships bugged ?

[Efaferal]

I am in early game with tech level 1 under research
I discovered a system with 3(!) derelict fleets orbiting a small planet.
I ordered construction ships to repair the derelicts.
1 frigate was successfully repaired.
any ship larger than a frigate goes into an infinity repair loop with not all equipment repaired and the construction ship sitting with empty cargo and fuel not being consumed.
I redirected a construction ship to repair a nearby frigate and that ship was successfully repaired.
The largest ship I have researched is frigate.
Am I being prevented from repairing the larger ships due to my ship size tech? or is this a bug?

[Radamanthe]

I also thought there was a bug while repairing an abandoned station early as the repair percentage did not seem to advance. I had a doubt several times when checking, but in fact 1° it was very long and took ages (like ~20 years), 2° I think that the percentage update is not barely periodic but some kind of event based, sometimes giving the feeling that it does not evolve at all.

Big abandoned ships can take years too but eventually it's done. I suppose the rational is that techs you have no knowledge of drastically increase repair time.

[MatBailie]

I've not seen that happen; I've repaired planet killers.

I can watch as the hull is repaired first, then the damaged and destroyed components are repaired.

[zgrssd]

It is confirmed that Repair (and scrapping) takes a lot longer if there is a relevant difference in technology.
This can make it to the point where the progress appears stuck.

Just to be sure, do verify the gamefiles. They tended to break. A lot. And there might be damaged files in play.
After that, you should make a serious effort involving a timespan of at least 1 year.
If there is no progress on those scales, you might have a genuine bug.