My first instinct was regardless of the way this was being raised here, this teacher's behavior was either pushing or 'just' treading on boundaries, but I wasn't sure if I was overreacting.
Ds works across a group of schools, often directly with students, not in classrooms, and unexpected/potentially awkward situations are commonplace.
So I asked him if this was anyway questionable or perfectly reasonable?
His response was "Whoa!" "Someone needs to update his safeguarding training!"
He also said the code word was "weird behavior" and it all sounds "unprofessional."
Reiterated that safe guarding rules are there for everyone's protection and comfort and neither every teacher nor every child is beyond questionable behavior whether directly intentional, or subconsciously led.
He also pointed out that what sex anyone is, is neither here nor there in an era of gender and sexual fluidity, and he's equally cautious around male pupils as a whole.
Also asked him what would happen in his schools if this 'situation came to him as pupil or parent 'gossip' about a colleague.
He said he'd automatically report it up the line, and would expect the colleague would either be hotly denying events as claimed, or would say no intent behind it and be told it was poor judgement and would be required to undertake further safe guarding training, for everyone's safety and reputation.