Thank you for posting your question and welcome to the Ivanti family.
When it comes to scheduling a patch task, there is currently not an option to have run every other month. As of right now, you can set it to be once a month on a certain date of the month or a certain day/week of the month.
We would definitely encourage you though to submit your idea to our feature requests to see if we can add that option in a future release. How To: Submit a Feature Request