activity history missing after upgrade to 10.3.3-ce.0

After upgrading our Gitlab omnibus from 9.3.10-ce.0 to 10.3.3-ce.0, all activity history is missing from the activity stream and users' profile heatmaps from before the upgrade. Activity since the upgrade is correctly shown. The activity history is missing for all users.

Searching for similar reported issues, I tried "sudo gitlab-rake cache:clear" and clearing browser cookies; but that hasn't helped.

"sudo gitlab-rake gitlab:check" shows everything appears to be fine. What else can I check?

thanks, Dave