A client has a NGINX load balancer in front of IdmApps 4.5 SP3 Tomcat
cluster (two nodes). SSL is terminated in the load balancer and then a
new SSL connection is going to Tomcat (same cert on both LB and Tomcat).

The IDMProv, dash and rra apps work fine but the landing app is
displaying an error message sometimes when accessing it:

The URL /IDMProv/rest/access/ulp/items/images returned invalid JSON.

The "solution" is to reload the page a couple of times, then it's OK.
When you access the landing page after that it can load just fine or it
can show the same message again.

When the message appears then the icons for the My Approvals, Request
Access etc. are not shown.

Any idea what could be the problem? Any special requirements that need
to be fulfilled when going through a load balancer?