When we switch Cost Explorer perspective, the group-by menu is sometimes missing "Tag" option. This seems to happen if a non-default date range was set in the first perspective (e.g. Last 90 days). 

If we refresh browser or change Date range/Currency or Group-by, the Tag option will load.

This applies to all perspectives (we can't reproduce it in "All Openshift" perspective because that is the default Cost explorer perspective and Tag option is loaded when we first visit Cost Explorer page)

Steps to reproduce:

stage env, cost-demo account

1. log in and navigate to Cost Explorer pages
2. change Date range on All Openshift perspective to "Previous month"
3. change perspective to "Amazon Web Services"
4. click on Group-by to see the options -> Tag option is missing
5. change Date range to "Last 90 days"
6. change perspective to "Microsoft Azure"
7. click on Group-by to see the options -> Tag option is missing
8. change date range to Previous month and then back to "Month to date" and check Group-by options -> Tag option is available
9. change perspective to "Oracle Cloud Infrastructure" and check Group-by options -> Tag option is available, because the previous perspective was set to the default date range