Why does a csv with no X/Y info show up with X/Y info?

[PhilipWeeks]

This was pretty weird to encounter but I've boiled it down to a minimum set of reproduceable steps in ArcPro 3.1.5 and 3.2.2 (possibly other versions)

• Open a blank text document.
• Type columnname on the first line or any useable field name
• Type A followed by 7 random numbers on the next line and as many other lines as you like
  (The IDs it happened with were around A1021215 but I've found it happens with A0000000, A9999999, and random values in between)
• Save as a .csv
• Find it in the catalog pane of ArcPro, Right-Click and Open Table

The CSV contains just these ID values but it populates these additional columns:

Why?!

[BarryNorthey · Accepted solution]

It looks like Pro is interpreting the values in columnname as coordinates as explained here.