AMP gravity form is showing Validation error in inner pages

I am implementing AMP gravity form in one of my sites. I used a gravity form in the home page which looks perfect and it is valid when I check it in amp validator. But when I use the same form to the inner pages, the amp page shows invalid in google amp validator. The error is "The attribute ':openbrack:value:closebrack:' may not appear in tag 'input'."

However, the same form is working fine on the home page. Can anyone help me with this? I really appreciate.

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