I updated my 15.2 virtual machine with MATE desktop.
I can get in on alt-F4 to see what is running - I have no marco display manager or any MATE parts. I can get the login screen but it goes black on login.
I am going to put back Sunday’s vdi and install all but MATE updates.
For Leap 15.2, you need to use “zypper dup” at the command line for updating. And that would have told you to reboot (because of kernel update, I think “glibc” update and openssl update).
Continue to use “zypper dup” for updates until the final release (supposedly July 02). Then one last “zypper dup”. And, after that, resume normal update practices for Leap releases.
By the way, there was another update today. I just finished updating a VM. I will delay updating my main desktop (where I’m typing this) until I am ready to reboot – probably Thursday.