Greetings,
this can have a lot of different reasons, and without more details no one will be able to help.
- Do the hosts crash/reboot when disconnecting/reconnecting? Check their uptime.
- How long does it take a host to re-connect after a disconnect?
- What is the version of vCenter and the hosts?
Regarding the error log with vmware-usbarbitrator:
- Do you have any USB devices connected to the host and mapped to VMs?
Andreas