(I’d add that other websites that use Forminator don’t exhibit this behaviour – although I do use BPS Pro on those sites.
I’d also highlight that he sites with Forminator installed haven’t succumbed to the vast amount of spam received via the wpforms plugin. WPForms is very easy to use and provides an attractive output – although the free version is limited in scope. Perhaps I should change over the other sites at some point to an alternative contact form such as Forminator or Fluent perhaps?)