Using the latest Classic Kendo theme, when showing a grid with a pager, the button indicating the currently selected page has a background that's a function of the button's text color (opacity .2). This results in a background color that lacks sufficient contrast with the text color which is not compliant with WCAG contrast rules for display text.
#F35800 is the default primary button color in the default theme and F1D2C0 is the color that results from the interaction between a background with opacity .2 laid over the default background grey #F0F0F0. I've attached a screenshot of the PowerToys color picker showing the computed color of the button.
The button background color needs to pass all of the WCAG checks in the above link in our application and really should by default in my opinion.