Empty Subscribe and Share content

I’ve set up a Subscribe and Share relationship to copy bundles from a ZCM 2017 Update 2 zone installed on SLES 11 SP3 to a ZCM2020 zone installed on appliance.  I’m running into an issue where, when I assign specific bundles in the 2017 zone to the Subscriber, then go to the Subscriptions section in the 2020 zone and go to the Download Filter for the Subscription to the 2017 zone, clicking on the Add button under Shared Content is resulting in a blank area under “Select below shared content to replicate into local zone”.  If I remove the bundle that’s causing that to happen from what’s being shared in the 2017 zone, then go to the 2020 zone and pull up the available Shared Content, I get the expandable menu of bundles back.  Any ideas as to why that would be happening?  Which logs can I take a look at for clues?