Form not submitting on mobile with signature required

The signature works fine as a required field on desktop. I’m using this option with PDF Form Filler for mobile users specifically to fill-out the form. When the field is required, it has the Error message come up, but after submitting again it works (on desktop). On mobile, the field isn’t being recognized at all since it won’t send even after adding a signature. When it’s not required the signature also doesn’t show at all, on desktop or mobile. Any help with this?

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