trying to visualize the situation...I can think of a few things. The puck striking near the finger tips outside the pocket and the puck striking directly into the pocket and pulling the glove back. For any harder shot this is going to happen in hte latter situation. As long as the puck isnt coming out its not a problem. I fial to see how baby powder would help the situation unless its simply a fit/strapping issue. IF your glove is slipping off the hand then you have been selecting gloves that are too large for your hand. Try a Senior Medium or next size lower. Pocket size will be the same but the internals of the glove will fit you much better.
What I wonder about is how your holding the glove hand in stance or during usage. If you tend to let the glove drop back behind your pad(behind the plane of your body) the tendancy is to pull the upper body away from the shot extending the arm/elbow. This turns the hand sideways to the shot direction. Not much of the shot energy is taken by the glove and hand. The glove bends back tipping the pocket and allows the puck to pop out and into the net. Also, if you have excessive forward chest lean the same tendancy exists.
Pucks that are striking the outter edge of the pucket or near the finger tips are real bad. Tantamount to a "snow cone" for a baseball player. Fingers can be hyper extended and the puck will almost every time bend the glove back and blow right by the catcher. This is again a mechanics of the glove positioning in stance and during usage. There is also a visual depth perception issue involved. Have you had your eyes checked?
Many goalies hold the glove kind of tipped down with wrist bend to face the pocket out at the shooter. Basically you end up with the pocket of the glove pointed left or right to the post horizontal to the ice. To correct this issue my best advice is top change the glove positioning your using in stance. Do you have any pics that rep your stance well? can you get one? clarity doesnt matter so a cell phone image would be good enough. I dont want to see a posed shot. Standing in a relaxed stance on the photog's command go into your ready stance where the image will be shot at that exact moment. Rarely will a goalies posed stance and automatic response stance be the same.
try a glove positioning more like those pictured below. This is a "fast hands" postioning taught in Finland and Sweden that really gives solid glove performance. the puck entry int othe glove is from a stronger hand positon and visual tracking is MUCh easier. It also helps eliminate the glove dropping back behind the visual plane as the goalie retreats in the crease.
The glove tends to point more to the top corner of the net rather than at the posts. This is the glove positioning taught to my son by Jukka Ropponen. Also note the chest angle in the second image. This encourages center shifting into the puck path as well as provides a solid platform to execute save movments.