failed to form statements: invalid character 'ï' looking for beginning of value

With a freshly installed version of gron from Howebrew, I am getting the following error when trying to gron a json from a BloodHound output:

$ cat 20240325120043_users.json | gron
failed to form statements: invalid character 'ï' looking for beginning of value

I checked manually and the input json file does not contain the incriminated ï character. Is there any known cause / workaround to this issue ?

I am under MacOS Ventura 13.6.

Thanks a lot!