I have a question for this group. Have you ever known a cat to like avocados?

My kitty, Boogie, likes to lick the insides of avocado shells after I've scooped the flesh out of them. He will also lick the surface of a piece of cut avocado if he can. He doesn't take bites of it, only licks it, so it's not like he's eating very much. I've googled it and some sites say that it's generally not harmful to cats and dogs, but it does contain a toxin, persin, that is deadly to some birds and other animals, depending on the part of the fruit that is ingested.

Does anyone have any experience with this?