Riven unveil progress resetting after entering underwater area via archwing

[Jasieknms]

my melee riven mod requires me to find 16 syndicate medallions, i was in a capture mission with 2 other people and we found 7 medallions in total, close to the end there was a water section (just decoration pretty much, it was not needed to progress) and i accidently fell into it. my archwing activated and after i went out of water i lost the progress i had on my riven. wasen't sure if only was a visual bug, but even after the mission ended i checked and it was only 5/16 (I had 5 collected before).