BIG-IQ Device Management - Device is not available.

I'm working with BIG-IQ version 6.0.1.1 and I've added about 12 BIG-IP LTM running code version 13.1.0.3.0.0.5 devices and it seems that every day I log in, I find that one of the devices has gone red and says the device is not available.

 

The only way that I have found to correct the problem is to remove and re-add the device. I created a case with F5 and they said that this was a problem in the previous version, but has been fixed in this version. They also said that it could happen if the admin account password has been changed. (the password part is disturbing) I don't want the re-add devices everytime a password change takes place.

 

Has anyone encountered this? Do you have a solution?

 

Thanks