Board Game Arena

I have played a 3-player game: ?table=525608118
Winner +14 -> 228
2nd place -3 -> 135
3rd place -11 -> 254

My complaint is about 2nd place (obvously its me ).
Placing 2nd against opponents ~100 higher rated, I'd expect to gain not lose elo points.

I just checked - https://boardgamearena.com/table?table=525608118

You weren't second, you were joint second. That changes the calculation a fair bit. You'll have lost a small amount of ELO from losing to the winner (only small because, as you observe, they're considerably higher-rated than you), but gained some from tieing with another player who is much higher rated than you. I'm a bit surprised that adds up to -3 rather than a small net positive, but it's not very big either way so I wouldn't worry too much abobut the details.

In case you're not aware, you can see the calculation breakdown by hovering on the arrow symbol.