Parent Form -> Subfrom with Lookup Field - Desync on Parent Form Viewport

Parent Form -> Subfrom with Lookup Field - Desync on Parent Form Viewport

I have a Parent Form (Accounts) with a Sub-from (Documents).

The Documents form contains a lookup field for Accounts, however when the "Related Account" Lookup Field is  updated via the Documents form, the change is not reflected in the Accounts Form's - Documents Sub-form Table

How do I correct this?