Warning message about global variables when copying sheet

[JenniferMurphy]

I have a workbook with a bunch of sheets containing logs and charts of blood glucose readings. There is also another sheet with global variables such as BGXHigh, BGHigh, BGOK, BGLow & BGXLow. These are referenced in all of the log sheets. For months, whenever I need to start a new log, I just copy the current log and chart sheets and edit out the old data.

In the past, I guess I must have always copied the 2 sheets one at a time. Today, I selected both sheets, right-clicked, and selected make a copy. I then got an error message saying that one of the global variables "already exists" and offering me the choice of using that one or renaming it. The options are "Yes", "Yes to All", and "No". If I click on "Yes to All", I still get the warning message for each of the 10-12 global variables.

After the copy is complete (having clicked "Yes" each time), I check the Name Manager and the same global variables are still there and there are no additional copies.

If I copy the two sheets individually, I get no error messages. I also noticed that if I click "Yes", rather than "Yes to All", I get more warning messages.

Questions:

1. Why do I get error messages when I copy 2 sheets at the same time and not when I copy them individually?

2. Why do I get more error messages when I click "Yes" vs "Yes to All"?

Excel 365 (2019?) is a lot weirder and more finicky that 2007. I'm not sure it's better on net.