Workflow transition validator - "Skip validation for mail handlers"

[IT Support]

Hello,
in my workflow within "Create transition" is configured validator to "make one field mandatory" (basically, validator is checking, whether value was populated for respective field).
However, because it's "Insight object field" and it should be possible to create respective ticket also through the Next Gen Mail Handler, I would like to use "Skip validation for mail handlers" as Next Gen Mail Handler does not allow to populate Insight field directly.

But it does not work. Logs for incoming emails are showing, that field is mandatory also for "ticket creation from the email through the Next Gen Mail Handler". Therefore it seems, that "skip validation for mail handlers" does not work or is related only to Classic Mail Handler (which is deprecated).

Could you please suggest, how it could be solved ? One workaround is to move "mandatory field validation" to the next transition like 'Assigned' or similar (after the ticket is created), but I would like to still somehow achieve it during creation...

many thanks

Jira installation parameters:
Jira server v8.20.1
JIRA Service Management Application v4.20.1