When running any group report in Report Manager the Global Collections are missing. This can be due to special characters in the Global Collection name. As an example, if the Global Collection name is Smith's Collection. The apostrophe in the Global Collection name will prevent the collections from populating the list in the group report parameters page.
The current workaround is to remove any special characters from Global Collection names if this issue is encountered.
Engineering is working to fix this issue with WI 378316. Which will be added in a future release of CA Spectrum.