Having Excel run in multiple instances just to stop this minor bug is like using a cannon to kill a fly. The reason Microsoft stopped using multiple instances is because a single instance for all workbooks improves the user experience. Changing it therefore
diminishes the user experience (aside from this bug)....At least for our company this fix would shutdown three-quarters of our engineering tools.
This is a valid concern. We have little VBA use here, though we do have dozens of worksheets referencing each other. However modern machines are so much faster than in the earlier days that I'm not sure the difference would be perceptible. You might consider
trying it to see what impact exists. Perhaps you'd be surprised.
There's no question that a proper fix would have been a big help, but after this many years of a widely-discussed but unresolved problem, nobody is holding their breath for Microsoft action.
At any rate, for us this has been infinitely better than living with the problem. By the way we did not view it as a "minor bug." It was a complete work-stopper. When the sheet flip occurred without being noticed while typing, the new changes went into the
wrong sheet. Depending on the workflow, this sometimes replaced cells. This was a constant hourly problem and led to lots of lost work and unexpected consequences.