I think the answer is less about what has changed in their evaluation of Cunningham (nothing) and probably more to do with what might have changed in their roster/depth chart and the point in the season. In other words, Cunningham is constant, but the competition/needs for the Mr. Irrelevant roster spot changed and that has nothing to do with Cunningham.
With regards to earlier in the season, my hypothesis would be that they had drawn up some gadget plays for Cunningham before the game but then the game situations didn’t end up fitting what they had drawn up and/or what the other team was doing on defense didn’t fit well with what they had drawn up. I’ve been fairly unimpressed with the offensive coaching staff this season, but they are also not complete morons. I’m sure they have defensible reasons for the moves they do or do not make.