Ohh my..
You are absolutely correct.
I never did read the small print on the back. It is written that B side is mastered from a mono tape.
I thought that somebody knocked the mono switch over, while reaching for an ashtray or something.
But seriously, I just didn't expect them to choose to differentiate from the original pressing on purpose. Unless that first US pressing is also B-side mono.
My two reissues are both sides stereo though.
And I agree totally with you. First masterings are almost always safer bets in terms of audio quality.
To be fair, side A of this particular 'hi-end' re-issue does sound pretty good.
At least It sounds better than my two other reissues.
But Side B, is a buzzkill for me...
Anyway, thanks for mentioning that.
It partly solved that puzzle.
But I still can't figure out why they would go mono on B side.