How do you flag new common ancestors?

[Phoenix]

Originally Posted by Mary from Italy

Does anyone know how often "Common Ancestors" are updated?

My son tested recently, and of course we have loads of matches in common, but I was surprised to find when I checked his Common Ancestors that he has Common Ancestor trees for many of our matches which I don't.

There are apparently problems with Thrulines at the moment. I've currently privatised my tree to deflect a stamp collector, but before I did that, three people linked to my tree suddenly lost their Thrulines.

Are these new common ancestors simply not showing, or old common ancestors that you have suddenly lost access to?