I've had too for some time now already (can't remember if it started already before SFOS 4.5), and I've been thinking of reporting this but have failed to do so.
Looking at running processes via Crest, there are multiple instances of "harbour-situations2application server". Some of them can be easily killed, some spawn back. After device boot there are only one, but opening up the UI tends to cause another to be run, and then they slowly multiply (haven't been paying attention whether opening the UI triggers that or if it is something else). Edit: Looking at what you just wrote Heikki about single-instance launching failing, would this be that, actually?

And sometimes launching the UI also stalls at the splash screen / spinner, but I haven't been able to identify in what conditions that happens. It might be after killing away the extra ones but mistakenly killing also the "good one" in case the extra instances are somewhat zombiefied (but this is purely speculation).

I've not yet tried the new version but I am absolutely delighted to see that this app that I find being one of the most valuable ones is still being maintained!