I resolved the problem. All I did was to disable all update tasks for a couple of hours and pointed the clients to the ePO server as their repository. After a while the loop did not appear anymore in the agent logs.
Now I am rebuilding the super agent repositories that were intended for these clients, as we had replication problems because the agent got stuck in a loop.
I am not shure what the exact cause of the problem was but I think it had to with the outdated repositories, the MSI installer and sheduling of the update tasks (eventhough we use randomization).