It happend to me once but only because I landed short of the marked spot, then drifted to the spot. Nothing happend so I had to restart. I take it we must land on the spot directly.
Also make sure you have NO add-ons installed for that area. Installing add-ons like eg. Mesh could possibly result in moving the landing spot which will result in a change in the "Event trigger".
I had a mesh installed for South Africa, when I did saving the rhino mission it did not want to continue either. I had to remove it to finish.
Hope it helps.

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