R12.2.9 - Line Numbers in "Match to Purchase Orders" screen not in number order

Since we upgraded from 12.1.3 to 12.2.9 we have an issue where this happens:

1. Create Invoice
2. Click Match button
3. Search for PO and click Find
4. PO Lines are returned, but instead of being sorted by Line Number, the line numbers are sorted like this: 1, 10, 11, 12, 13, 14, 15, 16, 17, 2, 3, 4, 5, 6, 7, 8, 9
5. Instead of like this: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17

This appears to be in line with the numbers being treated as characters and not numbers.

This did not happen when we were on 12.1.3.

I have checked for profiles which might control this behaviour, but cannot see anything obvious. I might need to raise an SR but thought I'd ask here first in case others have come across this issue.