I have an issue with my Raspberry PI running Raspbian 9 hanging on startup - but not always. It will hang every other launch.
When the problem occurs, the launch first hangs with the last message
Starting Show Plymouth Boot Screen
it will hang here for a minute or two (usually it proceeds after like 3 seconds), then proceeds to show splash screen with message
Here it just stops, won't go any further no matter how long I wait. When I unplug the power and plug again, it will always boot properly.
I've seen this question but the author mentions he has changed network interface, which I'm sure I haven't touched. I haven't touched anything actually, aside from installing Maven, NetBeans, BlueZ and some Java libraries. And my Pi eventually boots up properly half the times.
What might be the problem? How to debug this issue further?