How to change the below explained validation from inline style to ms-form validation on migration from SP 2010 to SP 2013?

After migration from SharePoint 2010 to 2013, when we add an element and miss any mandatory field, we should get the validation errors.

But in my case, when I fill the Authorized Date field and miss any other mandatory field, then I get the validation errors in red as shown below:

And on inspecting the error message, we see that it is under ms-formvalidation class.

But when we miss the Authorized Date field and then try to add the item, we see this loading and it doesn't stop:

So we edited the web part and changed the CSR rendering mode from Standard mode to Server Render mode and then clicked on Apply. We saw the following message displayed under Authorized Date field in black color:

And on inspecting it, we found it as an inline style:

.

As per my understanding, If this is changed from inline to ms-formvalidation class, then the error will be resolved.

I need help on how to fix this and any other helpful suggestion on how to overcome the above mentioned problem.