When users navigate back to the homepage, if there is a slice being displayed, slice callback will be triggered. It will then check if this slice has any error hint, where NPE would occur if the slice turns out to be null. Hence, add a null check before checking slice hint. Fixes: 148158780 Test: rebuild and navigate back to the homepage. Change-Id: I2b04dc0d64a223cc85f6af55b2ae2dbc5f3e1f40