`validationMessages` not working via `validateOnly`

I have a form that uses

validationMessages

validationMessages

to customise validation messages returned to the user. These messages only appear to work when the form is validated via

getState

getState

, never through

validateOnly

validateOnly

.

I am using the

updated

updated

hook, and the same issue happens when I use

afterStateUpdated

afterStateUpdated

on components.

Has anyone else bumped into this and is there a way to revolve it? Should I open an issue?