in latest v9.3.1 it appears GridFilterCell isn't passing properties shaped as 'isRequired' on DatePicker popupSettings 

this does seem to be a regression because i just recently noticed it in latest upgrade which we need for other bug fixes.

i pursued patching myself by populating animate in GridFilterCell.mjs which seemed to work but then i got warning for the next required property "appendTo". however, populating appendTo yields warning "Warning: Failed prop type: Invalid prop `appendTo` supplied to `Kendo React Popup`. Validation failed." so it's not easily reconcilable that way... therefore i tried removing isRequired on all 3 DatePicker popupSettings properties which of course avoided warnings and i didn't see any negative side effects.

here is a codesandbox repro minimally tweaked to include a date field from kendo grid's "getting started" demo: https://codesandbox.io/p/sandbox/cool-sanne-d4tp85

admittedly this is just a warning but it does create unnecessary noise in browser debug which detracts from issues truly requiring attention during development.

screenshot with the warning from that demo repro: