-snip-
That's just an example on how an unrelated address ended up in a wallet with seed.
Anyways, let's wait for his reply to this before we hypothesize:
Okay, how about the other addresses, are they the same as the addresses from your newly restored wallet?
If it's a
no, your and
this (
1st paragraph) scenario is correct
If yes, it's most likely that old version bug or something else.
< re-post edit yes->no >