The default sort order of mixed numbers & text is usually numbers, then text. Airtable seems to do symbols, alpha, then numbers.

For example, normally in in Excel stored as text:

1

18

1a

Airtable sorts as

1

1a

18

While not necessarily a bug (which is why I put it here instead of the other forum), it is not what is typical for other applications so it is inconvenient.