I wonder if you ever noticed that Coral Multifield (granite/ui/components/coral/foundation/form/multifield) dialog item does not block user from submitting an empty required field. At the same time, Granite multifield (granite/ui/components/foundation/form/multifield) dialog item does the job well.
So, please, share your experience: do you have the same?
P.S. My dialog configuration with Coral widget onboard