Issue w/creating a range of serial numbers when receiving parts-rece

[system]

i can't create a range of serial numbers when receiving a serialized part in the receipt entry.

on the part maintenance, serial number format, i have this part as numeric.

when i go into the 'select serial number' box for this part, under create serial number tab, i can't select 'add range of serial numbers'. it is greyed out.

but what is strange is that if i go to the format tab in the 'select serial number' box for this part, it shows as 'alpha numeric' even though i've confirmed that is is numeric in part maintenance.

any advice?