Well, I guess the mute is now active:
```
# ceph health detail
HEALTH_WARN 4 OSD(s) have spurious read errors; (muted: OSD_SLOW_PING_TIME_BACK
OSD_SLOW_PING_TIME_FRONT)
```
but I still get emails from the alert module reporting about
OSD_SLOW_PING_TIME_BACK/FRONT. Is this expected?