Performance: Live Roadmap may take an unacceptable amount of time to load

Issue Summary

The Live Roadmap may take an unacceptable amount of time to load all the items.

Steps to Reproduce

Select a Program and a Release/PI in the top/tier1 configuration bar.
From the left navigation, go to Programs > Roadmaps
(Leave the default, ie 'Work' set to 'Program Increment/Release')

Expected Results

The live Roadmap loads in a reasonable time.
(i.e the load of each chunk of 25 items should be loaded in less than 2s)

Actual Results

The live Roadmap loads in an unacceptable time.
(i.e the load of each chunk of 25 items can take more than 15s to load)

Workaround

Currently, there is no known general workaround for this behavior. A workaround will be added here when available
In some cases, we have seen that selecting the Portfolio in the tier1 filter instead of the program may help to load the roadmap a bit quicker.