Jeff Hawley shared on Twitter that he thinks Google not only is showing how-to schema more randomly and less often but also changed how they function a bit. This, he said, coincided with the November update.
He said on Twitter “Google appears to be more selective (or random?) about displaying the HowTo SERP features. I’ve noticed a huge decline since the last update. I feel like it might be even since Nov update.” I am not sure if it would be related to the November update, but who knows.
In any event, I checked RankRanger’s feature tracker but it lumps both FAQs with How-Tos and doesn’t go that far back:
So it is hard for me to confirm this with the tools.
He did also say that the behavior changed:
Did you see this change? If so, let us know.
Forum discussion at Twitter.
Update: More data from RankRanger: