This is happening as Hub 7.x tries to disallow a bulk size of 1 and imposes a "floor" of 100 whenever it thinks the consuming probe supports that.
Please upgrade NAS to latest supported version & hotifx level as well.
e.g., logmon was trying to make a connection to the hub. Because the hub was trying to force the connection to use a minimum bulk size of 100 it was causing a problem. By changing the hub to allow it to default back to 1 resolved the issue.
To resolve this issue two new keys need to be added to the hub in raw config:
bulk_size_floor = 1
default_bulk_size = 1