In Mobile, mandatory fields inside an hidden SectionExpandable don't seem to work.

If i try to submit the screen when SectionExpandable is open, mandatory fields are validated.

If i close the SectionExpandable, mandatory fields validation are ignored.

Submit with field empty, but SectionExpandable closed:

Submit with field empty and SectionExpandable open:

Thank you,

Vasco Mendes

If I remember correctly (correct me if I am wrong), content inside an expandable section is lazy loaded only when it is opened.
So as far as your application is concerned the input field doesn't exist.

But I agree, even if this is the case this is a bug, or at least we should have the option to disable the lazy load for these sections 

Eric and Vasco is true, the expandable section has lazy loaded behavior. That is, only when it opens will it carry what it has to carry, when it is closed, does it behave as if it did not exist.

And that's why Vasco is going to ignore the mandatory fields.

I hope I could help.

Best regards,
Nuno Miguel Verdasca