Haven't noticed that I often do -- every once in a while I will misspell a word because the correct spelling "looks wrong." I've noticed that it often feels like the effects of semantic satiation[1] -- perhaps the two are cognitively related? Usually I will catch it when I have a spell checker on hand, but I didn't when I was writing that comment.
I think you were maybe drawing some parallels with the word "decriminalization" in your mind -- which makes sense, because the word is being used a lot (with news of marijuana regulation and such).
[1] http://en.wikipedia.org/wiki/Semantic_satiation