Javascript validation stopped working on different sites

I have Form Manager installed on several sites on different servers and all of a sudden validation stopped working correctly.

If all fields are blank validation works correct, but if I fill in 1 character in a field that’s validated as an emailaddress validation doesn’t tell anymore that this field isn’t filled in correctly. Even though the 1 character doesn’t match the validation values for an emailaddress. See the form in the url below:

http://www.restaurantchristian.nl/contactformulier/

I also created a anti-spam field (where only the character “6” can be filled in), this used to work, but also stopped working. It’s the 4th field in the form in the url below. Same thing for emailaddress as above in this site. I choose as validation type “email” but I can fill in 1 character and validation doesn’t work anymore for that field.

http://www.hardgras.nl/contact/

I’m sure it used to work. And the strange thing is, that different sites have this problem, with different versions of wordpress running, but also on different servers and different browsers and OS. Even my local server has this problem. That’s why I have absolutely no clue what’s happening. 🙁

Does anybody have a clue?

https://wordpress.org/plugins/wordpress-form-manager/