Has anyone else experienced any issues changing (upgrading online or changing date by telephone for example) full Y tickets recently?

My last two TA-booked full fare short haul Economy returns allowed me to upgrade the outbound leg online but not the return, despite having availability in J - I would get a "temporary system fault". This is inside the 24 hour before departure window. For the first booking I got the ticket desk at LHR to upgrade the return leg, and they had some trouble - the system would not let them and the guy had to "force" it (his words) and issue me a paper ticket. The second booking I had the same thing - outbound Y upgradeable online, return gives an error - but I didn't bother pursuing it. However, I then needed to change the return date of this flight and phone up to do so (as online date change never works properly for TA tickets). They agent was unable to revalidate the e-ticket and I had to go to the airport ticket desk to sort out - this process is normally super smooth.

Personally, I think there's something wrong, maybe with the way our TA is booking the tickets - who knows. Unfortunately, on contacting BA with ticket numbers, booking references and detailed descriptions, I got - as I half expected - a totally useless response.

I hate to let a full Y fare go without spending a few quid for the Club TPs, so this will be very annoying if it continues.