InDesign 21.0.2. Language: UK English.

Immediately after a "You have not entered a valid cell range" error when trying to import data from an Excel file, typing reverses in the cell range field, i.e., 'print-area' becomes 'aera-tnirp' or 'A1:D5' becomes '5D:1A'.

This isn't a consistent error. By the way, both 'print_area' and 'A1:G50' are valid cell ranges. Resaving the .xlsx file, even down to a .xls, does not resolve the issue. Named ranges do not appear in the cell range drop-down.