This is the exact same thing that happens to me and I also have a mac. Could this be an issue that poser has with mac?

false1 posted at 7:10AM Sat, 27 June 2020 - #4393127

I have a similar issue in 11.2 Mac. First the parameters dials cease working, then if I try to select a different object I'm unable to. I'm able to command-save though so I restart Poser and keep at it. Tends to happen about once a day.