Thank you posting!
I can see that you have also sent a direct email to firstname.lastname@example.org with the same question, and I have just sent you my direct reply.
For the benefit of anyone else following this thread, I am pasting the relevant portions of my direct reply here:
"In short, the source of the problem is internal to your new Mac. It is not a problem within the TBT3-UDZ docking station. The internal limitation of your new Mac can be worked around by purchasing an inexpensive adapter based on DisplayLink technology and connecting that adapter to your TBT3-UDZ.
To expand further, you mentioned in your support forum post that you:
“I just finished setting up my new M2 MacBook Pro, replacing my Intel-based 2020 version.”
The Apple MacBook Pro (13-inch, M2, 2022) laptop with an Apple M2 processor is limited to a maximum of one external display via a Thunderbolt connection. Apple calls this out under the ‘Display Support’ section of their technical specifications here → https://support.apple.com/kb/SP870?locale=en_US
We also speak about this limitation in more detail in our recent blog post here → https://plugable.com/blogs/news/how-many-external-monitors-can-i-add-to-my-m1-or-m2-mac
Since your new Mac is limited to one external display only, this is why only one display connected to the TBT3-UDZ is working when connected to the M2 Mac.
Your older Mac based on an Intel processor does not have this limitation (it supports two external displays), which is why both displays work when the TBT3-UDZ is connected to your Intel-based Mac.
The internal limitation of your new M2-based Mac can be circumvented by adding a product based on DisplayLink USB video technology to your setup.
For example, the Plugable UGA-165 adapter → https://plugable.com/products/uga-165 is a USB 2.0 device based on DisplayLink technology. The UGA-165 adapter will allow you to connect one additional display up to 1920x1080 resolution to your M2 Mac. The UGA-165 adapter has a built-in DVI video output. We also include one DVI to HDMI adapter and one DVI to VGA adapter to use, if needed. Please note that the video cables themselves are not included.
You could connect the UGA-165 adapter to one of the USB 3.0 ports located on the back side of the TBT3-UDZ dock in order to connect one display, such as the 19-inch ViewSonic display you mention. You could then connect the ‘other’ remaining display to one of the video output ports built-in to the TBT3-UDZ.
Please note, you will need to install the DisplayLink Manager application on your Mac in order to use the UGA-165 adapter. We have detailed installation instructions available here → https://kb.plugable.com/questions/1185378
Should you elect to move forward with a purchase of the UGA-165 adapter and find that the adapter does not meet your needs, we do offer a 30-day no-hassle return policy for all products sold by Plugable and fulfilled by Amazon."
With all that said, moving forward we would ask that you reply only to our direct email, in order to help us keep all communication in one place for this specific case.