I use Sketchup make 2017 since a few years but it looks not stable at all. Sometimes, with a logic that I don’t get, when I try to zoom in the draw disappears so I can not work on the details.
Share the file so we can see what you’ve got. There’s surely something strange with the way you’ve created your model.
What version of Mac OS are you using now? Please complete your forum profile.
Clipping perhaps?
Might be but who knows without seeing the file. There’s certainly not enough information provided by the OP to diagnose that for sure.