Step by step instructions on how to reproduce the problem
Try entering a negative value in the filter column using the StackBlitz example here https://stackblitz.com/edit/react-dx7cna?file=app/main.jsx
This works using "ES" as locale (your example) https://stackblitz.com/run/?file=app/main.jsx
Github issue here https://github.com/telerik/kendo-react/issues/897