Pending contact snackbar and add contact FAB are sometimes displaced

The pending contact snackbar sometimes appears in the wrong place, with a blank space below it and overlapping the FAB. After the snackbar is hidden, the FAB doesn't always return to the right position.

I've seen the first problem on the Huawei Ascend Y330 (Android 4.2.2) and the Vivo Y11 (Android 4.4.4). I've seen the second problem on those phones and also the Honor 8A (Android 9).