Strange spatial structure of CAPE and PE on the Massif Central (french mountain)

I use a lot ERA5 to perform climate services studies. I have observed strange structures on the Massif entral mountain in France in the parameters CAPE and PEV (Potential Evaporation). I join a figure of the PEV cumulative for the 5th February 2022.

Has somebody observed something similar ? 

What can these structures be related to?

Thank you for your return,
Blandine

With the figure...