I'm afraid I still don't understand exactly what you say has happened.
Your autorec was the expression "Wundersch.n"? You do not have fulltext checked?
What was/were the title(s) of the programs that were recorded? (I'm still not sure if there's just one, or several)
Looking at the list of episodes for the german broadcasts of Joy of Painting ( https://de.wikipedia.org/wiki/The_Joy_of_Painting/Episodenliste ) I don't see a match for "wundersch" let alone any other part.
As to why the match has changed - perhaps because time has passed and there's no longer a match in the programmes due to be broadcast?
And why do you think the recording(s) that you do have were made because of this particular autorec?