Usually, on taping days, three episodes would be recorded, then a break in the production (partly to allow a new audience to enter and get situated), and two episodes would then be taped, making a full one week's worth of episodes.
In this particular case, maybe Dick Gautier and his then-wife Barbara Stuart, had to leave for some reason (like an illness, or stage performance somewhere else), and led Brill/McCall to come to the rescue.
The Watergate hearings DID cause delayed airings that would've led to what you had in mind (though I'm NOTruling that out), but I would almost count that out, since same couples rarely appeared over two consecutive weeks.
Late in the original series, and of course on the 80s version, they often relied on three different couples each day, which was okay, since the game did not have "returning champions."
