Kendo Grid (Angular 2+) Can't filter number Column

Using the official grid filtering example from Kendo Plunker link, If I enable the filter for the ProductID field then the filter does not work and I see the following error in console. Basically, none of the numbered column filter is working. However if the data type is string it works.

ERROR:

ERROR TypeError: (d.ProductID || "").toLowerCase is not a function
at eval (eval at t.compileFilter (VM1859 kendo-data-query.js:NaN), <anonymous>:3:29)
at Object.t.count (VM1859 kendo-data-query.js:1)
at Object.t.process (VM1859 kendo-data-query.js:1)
at AppComponent.dataStateChange (VM1970 app.component.ts!transpiled:22)
at Object.eval [as handleEvent] (VM1971 AppComponent.ngfactory.js:23)
at handleEvent (VM856 core.umd.js:12108)
at callWithDebugContext (VM856 core.umd.js:13567)
at Object.debugHandleEvent [as handleEvent] (VM856 core.umd.js:13155)
at dispatchEvent (VM856 core.umd.js:8720)
at eval (VM856 core.umd.js:10882)

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