Hi,
Same problem here on 2 mac.
Soft : DisplayLink Manager 1.3.0 on Big Sur 11.2.3.
Hardware : macbook pro intel 13" with a UD-ULTC4K-EU
and one macbook pro 15 2019 with a UD-ULTC4K-EU.
The problem occur each time we are playing a video on external display or during a webmeeting.
This is just a nightmare !