An incident will be raised for NGA to investigate the faulty port(s) and repair where necessary
And in the mean time a port swap is done. That port swap is entirely random and can be on either of the 2 Vendors DSLAM's.
The routing is virtual. Only a tie pair needs changed to swap port, wether that port is on the same DSLAM or another DSLAM.
Not only can I link numerous threads where a port swap has been from 1 DSLAM vendor to another, but there's a thread on kitz where a user went back and forth TWICE while OpenReach were trying to find a working port.
No idea where you get that a random port swap can't change DSLAM Vendor.
I'm aware you with for OpenReach and I take much of what you say as gospel and have learnt a lot from your posts.
Your assumption above is incorrect though.