fix

Author: adolgachev

src/material/chips/chip-grid.ts

@@ -305,6 +305,9 @@ export class MatChipGrid
   registerInput(inputElement: MatChipTextControl): void {
     this._chipInput = inputElement;
     this._chipInput.setDescribedByIds(this._ariaDescribedbyIds);
+
+    // If ids were already attached to host element, can now remove in favor of chipInput
+    this._elementRef.nativeElement.removeAttribute('aria-describedby');
   }
 
   /**
@@ -364,6 +367,8 @@ export class MatChipGrid
    * @docs-private
    */
   setDescribedByIds(ids: string[]) {
+    // We must keep this up to date to handle the case where ids are set
+    // before the chip input is registered.
     this._ariaDescribedbyIds = ids;
 
     if (this._chipInput) {