I have the same problem, new passport but unable to update my details online in my account. So now have to go to a check-in desk every time - yet the whole benefit of OLCI is to AVOID having to go to a check-in desk!

What a shocking apology for an airline BA has become.

Edited to add, just spent 30 minutes on hold to BA to get it changed by an agent and listened to multiple recorded messages extolling the virtues of OLCI, how it is quick and easy and enables you to get your Boarding Pass on your phone . Even the agent told me I could have changed my PP details online and there was no need to be phoning BA to do it . I told her it couldn't be done and also told her about Flyertalk whereby this is an issue that others are also having.