[James2001]

The opening titles and break captions in both of those episodes look fine, so it suggests that it's something that was done during the production of those two episodes, rather than anything to do with degredation of those tapes or something set up wrong during a more recent transfer.

Unless they've done similar to the 'Doctor Who restoration team' approach where they do a really good quality restoration of those reused elements and then swap the source material out each time? That would imply a level of 'remastering' which I simply don't believe is taking place however, like I said previously there have been very obvious video tape errors which could easily be massaged out but haven't been, so I'm quite certain nothing is happening other than digitisation.

I think it's very fair to say the sort of restoration that goes into Doctor Who (and other old BBC programmes) is far too time consuming and resource intensive to be used on something that's having to deliver 5 episodes a week, and only on a comparatively minor streaming service.