Receipts and payments exclude tax amounts after upgrading to 20.8.31

GST should be applied on the invoice.
If you specify applying it also on the reciept and payment you are asking Manager to apply it twice ie about 20% not 10%

In my opinion Manager should disable the tax selection on a line item with accounts receivable or accounts payable selected

The equivalent for journal entries would be as shown in Inconsistency in Tax-reporting - #20 by Patch