for the most part when you are in the detail picture viewer and I click to change the zoom between fit and 100%, at random times it will kick me out back to the Photo Grid instead of zooming in to 100% or going from being zoomed to 100% to back to fit. I have checked my mouse for mall function I also unistalled and reinstalled Lightroom. This has greatly affected my workflow and I don't know what else to try.
Are you making the two clicks so fast that in fact you are triggering a "double-click"? On my Mac system a double-click on an image in detail, in both Lightroom Classic and the Lightroom desktop apps, reverts to the Grid. Same applies in reverse, i.e. "double-click" on a thumbnail in the Grid opens the image in Detail view.