I haven't seen any other sources on this story (they all link back to GWP). From the scant information presented in the article, the mask was, at the very least - the straw that broke the camel's back for the judge.

This isn't the first, second or even third such case. They are becoming more common

https://www.securitylawbrief.com/covid-face-masks-and-parental-custody-rights/