DatePicker input not valid on IE 11

Hello dear fellows.
I have a problem with Date Picker. Its costum datepicker that i downloaded from the Forge.
It works fine on Chrome, IE 8, 9 but on IE 11 it gives me that the input itsn´t valid, even if it´s nulldate.
And there is like 6 datepickers in one page as filters. And if i use IE 11 i have to pick a date in all datepickers as i can search for any record.
How could i solve this problem?
I add  an image, that shows what happens when i try to search. Attention, this variables are not mandatory.
And should let submit, but as its get that the input itsn´t valid wont let me submit.
Hello Slavi,

From my understanding, you're not using the platform's default date picker is that correct?

my best advise to you is to post your question in the component that you've downloaded so that the owners of it can pick it up.

Pedro Cardoso