I have noticed this behaviour several times with many people. Once the contract of employees (such as PhDs, Postdocs, ...) ends, Professors/employers cut the communication with them even if projects or articles are still going on.
Those PhDs or Postdocs then need to finish the project/papers on their own, in a kind of isolation, i.e. with no or very limited scientific support and feedback from their previous employers.
Therefore, I do not understand the reasons why Professors/employers reduce drastically the communication and scientific discussions with their ex-employees about works that, sooner or later, will be published with their names over.
I mean, at the end, the articles that will be published by ex-PhDs or ex-Postdocs will be additional papers also for Professors/employers. So, why this lack of communication (and interest?) by Professors/employers towards ex-employees who will work for free to finish the articles?