I couldn’t reproduce it either for a second time. I was sending MIDI clock to the MIDI OUT or MIDI SOUND ports of Minilogue. I’m not 100% sure of it if there was feedback in a MIDI track but I can’t see how this is related to the MIDI clock settings (I remember certainly getting a crash notification when I checked an output port for the MIDI clock while the transport was on).
On a side note, it would be nice though for the future that those feedback situations don’t make Cubase crash and display instead a more informative warning. In complex projects they are difficult to spot.