This is going to be a hard one to judge because I see chatter within the SEO community and also many of the tracking tools are lighting up. These are all signs that there was a Google search ranking algorithm update. But truth is, this can be directly related to the featured snippet deduplication change on January 22nd.
What I am saying is that the tools might not be ready to process the change and thus are showing changes to what is listed in the Google search results for the queries they track. Also, SEOs might be noticing those changes in those third-party tools and potentially also noticing changes in traffic because of the deduplication efforts.
Here is some of the chatter in WebmasterWorld:
Some of the tool providers need to make updates:
So what you will see below is likely related to the Google featured snippets change and not necessarily a ranking algorithm update:
So I really doubt Google did an algorithm update, outside of the featured snippet deduplication change. But if they did, it would be hard to know…
Forum discussion at WebmasterWorld.