Just pitching a vial and not aerating, is very likely your problem. A low yeast count to begin with, and conditions not favorable for reproduction.
If you can keep it in the fermenter, you can make another beer and then move this onto the cake of that one when it is done.
Originally Posted by danielbt
I think that the problem has more to do with only keeping it in primary for 8 days. Why did you transfer to secondary?
Unless the temperature went low enough to drop the yeast, this will not be a problem. The yeast that is doing the work is still in suspension. I believe the yeast in the cake are still good to reduce diecetyl, and clean up some off flavors, but it is not making any alcohol.
Originally Posted by michael.berta
After I started using pure O2 my attenuation when up. I haven't had the 1.020 curse since....
I've never used O2, and have never had the 1.020 curse.