The fact the you say the same thing happens on two macs is suggestive of a “Rhino Problem” BUT the problem you describe sounds like an operating system problem. I have seen Rhino crashes but they are infrequent. I have also seen a lot of problems in Rhino that clearly were the result of system bugs.
Are the two macs the same model? Are they running the same operating system?
Someone else just reported a similar problem here:
One common them is that you are both using Intel (Yuk) graphics processors.
The other report said the problem occurred after “upgrading” to Catalina. Are you running Catalina?