I can confirm similar behavior in a resonance analysis I did some months ago using CalculiX 2.19. I reduced the mesh size so fewer equations needed to be resolved (for me, any mesh resulting in less than 25000 equations worked). At the time, I thought it was something wrong with my machine like a lack of RAM or something like this.
At the time I didn’t get any errors, the analysis just stopped, and even though I’m not sure when I think the last message was something about matrix composition just after the frequency analysis was complete (first step).