I have seen this multiple times with these slim, small, portable spinning disks - not with a HUB but direct connection in my case.
They use quite a lot of power and the USB Port might just barely be able to meet that demand - and drop out on peaks.
Changing the port might help, or using a different hub with it’s own external power supply.
They worked just fine in low demand day to day usage.
But when reading a lot of data - like when doing a full backup -
or when writing a lot when (re)storing a huge amount without pause
they where unreliable in this fashion.
… lack of power …
I too would recommend a dedicated external power supply for an external spinning disk, and even for an SSD.
Just to give you an example, the mouse I am using here is already very old in terms of when I bought it — it had been unused for many years — but it’s a wireless and rechargable Logitech laser mouse. The wireless receiver doubles as the charging station, and even though it connects to the I/O panel on the back of the computer housing via USB, it does have its own dedicated wall power adapter.
And that’s just a wireless mouse receiver and battery recharger. A storage device draws a lot more current.