Studio Display shows 3 dots then goes black.

Apple Studio Display working fine when I left for a meeting but when I came back and woke up the computer, it stayed black. Not showing up in Displays in System Settings.

So I...

• Unplugged thunderbolt cable, waited 10 seconds, plugged it back in. Nope.

• Tried both of my standard thunderbolt ports on the back of my Mac Pro (2019) near the top. Nope.

• Unplugged power to monitor, waited 30 seconds, plugged it back in: 3 blinking dots then black.

Finally switched from one my Mac Pro's standard 2 TB ports to one of the top TB ports and it works. I have the W5700X 16 GB and its TB ports work for monitors, too.

Does this mean my Mac Pro's TB ports have failed for video?