Filter Liquify doesn't work on Mac mini with eGPU

[alpenaffe]

I want to use the filter -> liquefy in Photoshop 2021 and get the following error message
The Liquify command could not be used because a volume error occurred.

I work on a Mac mini 2018 with Catalina, an eGPU Blackmagic and Photoshop 2021

It works perfectly on my Macbook Pro without an external graphics card

[alpenaffe]

I connected the eGPU on my Mac Mini via USBC and connected the two monitors on the eGPU one on via USBC and one via HDMI, then it works