mixmastermark

Booked a RT flight with British Airways SFO-LHR for a work trip to the UK. LHR was just a positioning airport for onward travel.

Once I firmed up where/when I needed to be in UK/Europe, I booked a separate connecting one-way BA flight onward that departed a couple hours after landing, LHR to GLA.

To begin the trip, when I arrived at the BA counter at SFO to check my bags, the agent told me I cannot check my bag all the way through to Glasgow, even though it was also on BA, albeit on a separate PNR.

I was puzzled as to why BA wouldn't check it all the way through, as I had to claim my bags at LHR and recheck at the BA counter to GLA. She said it was a new policy with BA as of last fall?

In my experience, I've been able to check bags through to final destination, even on separate PNRs, as long as it's the same airline.

Oddly enough, on the return, I had a separately booked BA flight TLS-LHR to connect with my return leg, LHR-SFO. The BA agent at the checkin counter at TLS checked my bag all the way through to SFO no problem, even though it was on a separate BA reservation.

Was the BA agent at SFO mistaken? (I did question her, but didn't push as I was getting close to baggage cutoff time)
Or is this a specific policy on flights within the UK?

Thanks for any insight!