Ejected disk improperly errors with Time Machine

[bargbill]

OSX 10.14.5
I am getting ejected did=sk improperly after time machine runs.
I have two external drives in my IMac
4T Manual Backup where I put changes to what I am currently working on
4T time machine
The backup on time machine is good
And I am not doing anything that should cause the error warnings

 

[Lufbrarunner]

How is the time machine backup disk connected, Directly by USB via a USB hub or by network?

 

[bargbill]

USB HUB

 

[Lufbrarunner]

I had a similar problem, I moved the affected drive to a direct USB connection and all was well.