If a user updates an Account form, that subsequently updates the Contact Form via javascript REST, would a plugin devised for the Contact still fire on Post-Operation?

I have the Account form automatically create a new record for a custom entity called ValidContact, and I then I created a plugin for ValidContact that should be invoked when a field changes in the ValidContact form. The question is - Does the ValidContact form have to be manually interacted with for the Post-Opperation plugin to fire, or can it still be invoked if javascript action made changes to it from another form?