Mailgun app - template variables

I’m using Make scenario to send various emails from Pipedrive. In Mailgun I have a template, it accepts multiple variables and many of these are optional and they trigger appearance of various optional sections in email.

When I pass template variables Make insists that all variables are required and throws an error if any value is absent or null.

Is that an expected behavior?

I can’t see any good reason for this since Mailgun will accept empty variables without problem and it can be handled inside a template normally. Looks like unnecessary limitation not aligned with underlying Mailgun API