I would do the same exact thing I would do if they had linked me to Wikipedia. I would find the place in the article that states their point, look for where it is referenced in the sources, verify the reputability of that source, and then read for the claim in the source to see what it has to say about it. Especially if the source actually claims the opposite of what the article has written about it. Further, for Wikipedia, I would read through the Talk page for the article to see any mentions of bias or potential lies by omission.

Whether it being from Grokipedia or Wikipedia does not change the approach.