Check boxes look weird after upgrading

My check boxes in version 4.22.1 used to look like this:

image

After upgrading to v 5.2.4 I get this:

image

That's obviously not what a check box should look like.

The word 'check' disappears when the check box is unchecked.

Any ideas what might have caused this?

Check this thread: Migration to Radzen.Blazor v5.0