Unsure what caused this error to come up, as I've tried the same mission using a different design and the mission recognized the payload but my design couldn't make it to the location. The one thing that comes to mind that's different is that due to the size of this plane, I had to launch it from the DSC port (using solid rockets to get airborne) as I don't have the DSC runway yet. My best guess is that payloads get flagged as 'missing' when they touch water.
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