After upgrading to ITMS 8.5, a lot of packages in a package server were in pending state and those packages were downloading very slowly (or did not download at all. Staying in Pending state).
The package server had all packages in Ready state before the upgrade.
After updating the agent configuration and refreshing all packages, the count of ready packages increases but very slowly until stopping downloading at all (in spite of all packages were previously downloaded and ready).
If a package is selected in the package server tab in "Pending" state and "Force Download" was used, it will run the package check and set to Ready right away.
It was found that packages stopped downloading on the package server as soon as error "Cannot set bit range, DynamicBitset is not created" appeared in the agent log.
Problem occurred after upgrading from ITMS 8.0 HF6 to 8.5.