Good morning Support and thank for reaching out to us with your enquiry.
We are not aware of such a malfunction on 8.3 and to be more helpful we need to investigate for your specific case.
It appears the customisation could interfere with the base register (flds2>arp->fldcount), but it's pretty impossible to figure out with so small information.

We will take charge of your report and come back to you.

Best regards,

Giuseppe
HansaWorld Support