@WildTZ, glad you found your solution.
However, there’s one more question to be answered. In the cases you provided, were all the invoices in questions partially paid?
The reason why I’m asking this is that in the screenshots you provided, I still can’t make sense of the cash basis adjustment for withholding tax
No they were not all partially paid. In all the tests I did there was no partial payment.
This was a bug. Basically if purchase invoice total is $1,100 but amount due on invoice is $1000 due to withholding tax, Manager thinks $100 is partially paid and so on cash basis, instead of this invoice having no impact at all, it will have the same impact as if it was partially paid.
This is now fixed in the latest version (25.3.20)
Now when invoice is not paid at all, there will be no withholding tax liability on cash basis. However if invoice is paid partially (e.g. 50%) then withholding tax liability will be also at 50% on cash basis.