Edit to add 3/21/16: Since the publication of this article, the Oregon PAC and the campaign of Austin Petersen are advertising that it is still going forward. A written confirmation one way or another was requested from the Johnson campaign without response. The prior source was consulted and confirmed but nothing in writing officially from the campaign has been published. As far as all advertisements are concerned, the event is still going forward.
It had been previously advertised that Gary Johnson would be debating Austin Petersen at the Liberty Party of Oregon (PAC) Annual Convention on March 26, 2016; however, it has been confirmed with the Johnson Campaign that he will not be appearing. Long-time IPR readers will be aware that the PAC is not the Libertarian Party recognized by the State of Oregon nor the Party that holds the ballot access line which belongs to The Libertarian Party of Oregon (Chaired by Lars Hedbor). Any candidate that appears at this event might be interpreted by The Libertarian Party of Oregon as forfeiting their potential access to the Oregon ballot line. You can find more information on this dispute on IPR by reading the articles located here.
Edit to add: Further, the PAC is not the organization recognized by the Libertarian National Committee nor the Libertarian Party website as the Libertarian Party’s affiliate in Oregon. That distinction belongs to The Libertarian Party of Oregon (Chaired by Lars Hedbor).