Hello Godavari,
SAP NOTE - 75607 can address this issue.
Change the field status of the posting key from 'Opt. entry' to 'Suppress'."in OB41.
(Transaction: OB41 -> Field status -> Payment transactions -> Payment terms)
I hope it will resolve your issue. Please let us know do you still face any issues.
Thanks & Regards,
Lakshmi S