@Sally522
Just to let you know, a recent Airbnb "update" caused a glitch, which led to the number of beds/rooms in thousands of listingss, being erroneously advertised. Countless hosts are, undoubtedly, blissfully unaware of the changes to their listings, because Airbnb - as always - failed to notify hosts about the glitch.
As for the bugs - yes, it will hurt your hosts (and the income they rely on) badly, if you put this in the public review. From what you've already written - host did try to deal with the problem immediately, glowing reviews, past praise for excellent housekeeping, lovely couple - the current bug problem sounds very much like an unfortunate, unusual aberration, as opposed to a case of ongoing, willful neglect by your hosts.
I'm sure they're already stressed to bits about the sudden bug influx anyway. Much kinder to have a quiet word with them face to face, than potentially torpedo their little business by mentioning a (fixable and clearly uncharacteristic) issue in their public review, that absolutely will drive many guests away from booking with them in the future, and possibly deprive them of much-needed income. (In many markets, competition for bookings is so fierce now, that just one off-putting recent review, can be enough to destroy a listing)
If you broach the subject personally with them, with a little care and compassion, it gives your hosts a chance to rectify the situation, and it allows you both to leave things on good terms, rather than ending your stay with bad feelings on either side.