Same issue here. double "e", sometime no "d" or "a" and now and then the keyboard lags (words displaying on screen 3 to 4 words behind what I'm typing).
I had the lag issue on my Nokia E7 a couple of months before switching to a BB Priv, so after about 3 years of use.
Really a shame since typing turned from fun to annoying.
Both issues described above not happening constantly, so this makes me think they are both software issues.
I monitored CPU usage for a bit, but as of now, I couldn't pinpoint an app that bottlenecks the CPU.