Hi @LuisBa ,
Please try:

json(if(
equals(mod(length(split(variables('JWT Code'),'.')[0]),4),0),
decodeBase64(split(variables('JWT Code'),'.')[0]),
decodeBase64(concat(split(variables('JWT Code'),'.')[0],take('===',sub(4,mod(length(split(variables('JWT Code'),'.')[0]),4)))))
))
json(if(
equals(mod(length(split(variables('JWT Code'),'.')[1]),4),0),
decodeBase64(split(variables('JWT Code'),'.')[1]),
decodeBase64(concat(split(variables('JWT Code'),'.')[1],take('===',sub(4,mod(length(split(variables('JWT Code'),'.')[1]),4)))))
))

Best Regards,
Bof