MacBook Pro M1 new problem with 11.3 Display + Thunderbolt SSD

[lxmeta]

Hi Forum,

I just ran into a new problem with my M1. After BT seems to work now after all the fixes, I have an issue with a Lenovo ThinkVision X1.
The X1 has a built in USB2 hub (attached my network there) and a built in Full HD camera.
On top of this, I have a small NVME SSD enclosure I am using for backups.

I used to be able to use both devices at the same time. At least that's what I remember...
Both are showing up on the USB 3.1 hub.
Since the update to 11.3, when I attach the SSD for doing a backup, the X1 is loosing the USB2 hub and the Full HD camera. It is basically degraded to a simple display.
I need to detach the drive, detach the Screen, plug in the screen again, and then I have the X1 fully up and running again...

I did obviously call Apple support, but the guy was extremely clueless, and I need to do all 3 usual steps.
1) Run diagnostics (did not find anything)
2) Try the same with a different user (makes no sense, but how would he know). Obviously no change
3) Need to start in safe mode (which I don't have time right now, will do later)

Did any of you come across the same issue?
Is this something existing that I did not realise before?
I checked the specs, and I did not find any hint that this would not be supported. Why put in 2 TB/USB-C ports if I can only use one at once ...

Thanks,

 

[lxmeta]

Update:
Macbook going back to Apple.
The problem is much more sporadic, seems to have to do with a sleep/wake state.
Easy to reproduce, but hard to nail it down to very specific steps.
Definitely a new problem since the update to 11.3 on this machine.
Funny thing: My Mac Pro 4.1 upgraded to 5.1 running Big Sur has no problem, using a USB-C PCIe card... Completely unsupported but works great!