It could be many things, this is too much of an isolated incident to be termed as anything,
also your friend can only be dx DID by a professional, not by anyone on this board based on hearsay.
That behavior could be anything, from normal depending on the circumstances she is in...to abnormal and be part of a behavior in any of the many mental disorders out there.

But, Yes if she has DID, people with DID, can sometimes stop contact with someone suddenly for what seems like no apparent reason. Ive done things like this with a few people in my life, not to this extent, or so drastically but yes, its a possibility.

Cannot tell you for sure , however.

Puzzle_ Puzzle_