Hi Diana
I'm sure someone in this thread has mentioned getting water in the crown
causing it but I've been haveing the same thing happening and I water by
hand never getting the plant wet. It starts out either on the edge or even
in the middle of a leaf I've even cut most of the leaf off with a
sterilized knife and put Cinnamon on it but it doesn't stop it. I think
it's bacterial as in my case the leaf gets mushy and smelly.
Your second picture maybe the same thing as some plants might be able to
fight this whatever it is.
I getting close to the point of robbing a bank to buy some PHYTON-27 to see
if that will stop it.
Grow well and bloom magnificently
Dusty