Fault tolerance on the PHD2 link is not up to the task yet. You would maybe get more consistent results using the internal guider. I'm in the process of writing tests for this interface, further activities will probably improve the situation.
If PHD2 is connected to the mount first, device configuration will not be loaded by anyone.
If PHD2 fails calibration, it may just start looping without ever notifying the failure.
If a device is disconnected or its driver restarts, PHD2 will not recover the connection nor do the actual device connection by itself, and Ekos won't ask PHD2 to do it.
Also sometimes the driver connection will just fail on PHD2 side, and Ekos won't be able to recover.
So, a small list of hiccups that currently make guiding automation very instable. Add to this your KStars/Ekos crashes, and the outcome is cloudy. But, optimistic still
-Eric