I'm no expert and I try not to take this kind of stuff too seriously. I'd say if it works one way but not the other, it's fine supposing you're using the right side. There are strokes and uses that require both sides of the paddle and you may find the bend interfers with this. You will probably hear a few jokes about Warp Speed and all that.

I wouldn't worry too much bad habits, I've got a million of them and still manage to enjoy boating. Assuming the blade faces are shaped the same on both sides, I'd guess the blades flutter when the bend is facing aft because of "caster effect", same thing happens on a bicycle wheel if it does not have enough "trail". No cure that I can think of except to run it through a paddle straightner.

My guess is you will be building a new paddle soon anyway, just because they are easy and inexpensive to make, and for some reason, you can never have enough of them laying around. Most hardware store 2x4s are heavily kiln dried AND wet from laying around in the rain which results in lots of locked up stresses that cause shape changes as you whittle them down. Air dried wood is better if you can get it, but I know the difficulties in doing that. I have had good luck with Western Red Cedar 4x4s and 2x4s from my local hardware store because WRC is more stable, it is slow selling so the pieces have time to air dry and they store them in a covered shed. If good wood is not available, one solution is laminating the stock up from smaller pieces. This reduces the warping effect, but complicates an equisitely simple, inexpensive process. My last paddle took 2-1/2 hours to shape and cost $8.10.

Good Luck....

: Since you are experimenting with greenland paddles thought you might give me
: your view on something. I made my first paddle from a 2 dlr home depot
: spruce stud. I apparently cut away the parts that were keeping it straight
: so I have possibly the first "bent" kayak paddle. Both blades
: angle away from the loom a few degrees, but it is symetrical. The paddle
: seems to work fine on one face with the blades angling forward but if you
: flip it over it all over the place. Off the flutter scale. Having little
: to zero kayaking experience I am wondering if I can use this one or if it
: will be more trouble/create bad habits. It doesn't seem that it would
: matter anymore than having a power and a back face on a conventional
: paddle.