problem with search filters

I tried the search filter on the profile dr_doom97
when I try to filter the games by opponent rating above 1900 some of the games don't show up even tho the opponent is +1900 and the games are shown in the best rated victories. however, they do show up when I try above 1800 .

This link will find exactly what you want ( opponent rating strictly above 1900 ):

fbserv.herokuapp.com/games.html?username=eyadsd&opponentRatingmin=1900&autocreatecode=true&autostart=true

As to your problem with lichess search, I suspect that it is related to rating calculated as average rating and yours is below 1900, which drags down average rating.