Same issue here - Wisp Prime in Plains of Eidolon and Earth Mariana.
Had some similar resets with an Archwing mission as well (6 and 7 headshots while in archwing one without status effect).
Whenever I touched ground the progress reset, even though I got the 'Completed' message. No unlocks even on successful mission complete.
[Edit]: Reran Mariana Steel Path with Octavia to check if the reset only happens with special airborne mechanics 'Frames - but had the same reset issue again.