We've only just updated to 5.5 but I see the same issue on our openattic.

Ceph OSD Metric only shows placement groups, none of the other entries (Util, Util variance, Latency, OSD storage).
Ceph Node Statistics are all blank with no data points/data to show.

Default date they open with is in June but I've reset them to last 7 days and still only see the above.

Andrew