those ARE snails or slugs
 

snails or slugs will make holes like that
crownrot is what it says. the crown is rotting.
your plant look verry healthy except for the holes. to catch the snails check halve an hour after lights out. you will find them in the open snacking on the leaves.
otherwise i would replace all the potting material and wash the pots, because eggs might be clinging to it:feedback: