Navigate to - Financials > Configure > View Configuration
Values for fields Group Sales Tax On Invoice Pdf, Alloc Payment Tags To Appl, Auto Post Reverse Acctg Trans are not set by default ie NULL.
But if some uses the "Configure Organization" form to configure some field such as "Sales Invoice Footer Text", for these 3 fields Y comes auto selected and when user submits the form, they get set to Y.
This configuration (which was by mistake) causes issues in receiving partial payments.
Ideally if theres is no value, should be empty or N selected by default.