Submit button disabled after file upload type not allowed

Thanks for the great plugin.

I created a simple form with 3 elements.
1. File -> Allow Multiple checked, Allowed Types is “png”
2. Advanced File Uploader -> Allow Multiple checked, Allowed Types is “png”
3. submit button

There are 2 issues.
1. When click “Add Files”, the select image window will show 2 times
2. When add png file into File field, then add another png file into “Advanced File Uploader” field, all the png files in File field will add into “Advanced File Uploader” field
3. When add pdf file into File field, then submit, it will say file type incorrect, then i change it to png file or keep pdf file, submit again, the submit button will disabled and can not be function anymore.

https://www.ads-software.com/plugins/caldera-forms/