Yes Comtois has a pretty high shooting percentage at the moment, but it's not that bad considering that he has played just 15 games. Lundeström has a bit higher number although he has played only 8 games so far. Their numbers will come down.
Karlsson had 23,37% in the end of the 40 goal season and he played 82 games. He scored 43 goals in 184 shots. At the moment Comtois already has a bit lower percentage, 23,1%. In comparison, Ovechkin's career highest shooting percentage over the season was 15,4% last season playing 68 games and second highest was a year before it 15,09% in 81 games. That's 48 goals in 311 shots and 51 goals in 338 shots. His career shooting percentage is just 12,7. Another great goal scorer Stamkos has 16,9% over his career. He had one season when he had 20,16% but he played only 37 games due to injury. Although, Stamkos had 19,23% in 18-19 scoring 45 goals in 82 games with 234 shots.
So Karlsson was quite lucky scoring so much over the whole season even though he didn't shoot the puck nearly as much as some of the top scorers of the game.