I am experiencing this on a Droid2 Global running Froyo, but it was happening on a Droid Pro as well. It did not happen on my Droid running Cyanogen or stock Froyo.
When I'm typing in the gTalk app or using Tweetcaster, my text is auto-corrected. Even when I have auto-correct turned off in the keyboard settings. I use a lot of shorthand, and this gives rise to interesting conversations some times as auto-correct turns abbreviations like "DX" and "D2" into "PD" and similar silliness.
So, the question is: Is there more than one setting for auto-correct? If so, where is it hidden.
It seems to be global since more than one app suffers from it.