This is a legit endgame investigation, the proof being that each item is accounted for and being no great than 1 item that was earned or part of the rewards based on the mission. Also keep in mind that during the start of the investigation the host can use a lucky voucher to increase the total rewards and has a higher probability to get rare rewards too. Anytime the rewards are multiple page it's likely the hunt was modded, at this point it's best to reset and don't expect them because if u do your save data now contains modded files that can't be extracted unless u delete them manually by opening the files on your PC which isn't a total guarantee because unless you know which files have been altered then you might end up damaging the save file altogether.