mIRC didn't expect a third-party invite command like this where the target is not you. But you have 2 options.

1) Go into your channel's ChanServ settings and disable these notifications. Ask on a network's help channel if you can't find the specific option yourself.

2) On PARSELINE events supersede RAW events, and will have a 100% effectiveness. You just have a greater potential to break functionality if you're not careful.

Code:
On *:PARSELINE:in:?ChanServ!service@rizon.net INVITE *: {
  parseline -it
}

Well. At least I won lunch.
Good philosophy, see good in bad, I like!