I've written several plugins and have just noticed that every shortcode function that I've tested is being called twice. At first, I thought this was theme related, but it's not. It's generally not noticeable unless you do things like increment indexes (they'll be incremented twice) or generate forms (submitted twice), etc.
Can anyone share some wisdom on this? If this should not be happening, then I'll dig more deeply into my code. Just wanted to know if anyone else has seen this and experienced it.