Suddenly Unable to Select Entire Table or Entire Column (but I can still select an entire table row)

[jase71ds]

Within an Excel table, you can mouse over the top of a heading and you will get a downward-pointing arrow and the ability to select the entire column.
You can mouse over the top leftmost cell, and you will get a diagonally-pointing arrow and the ability to select the entire table.

I've lost both of these features ☹

However I can hover my mouse at the leftmost of a row and I still do get the left-pointing arrow and the ability to select the entire row.

I am running the business version of MS365 and I have other tables within this same *.xlsx workbook that are working entirely as expected. It's just this one particular table that I've lost 2 of the 3 "arrow" select options.

I've poured through settings looking for a wayward toggle. Nothing.

Has anyone encountered this? Any thoughts on what is going on or how to fix it??

Thanks.
Jase.