Nah these things are funny like that you can end up just like this with very close friends, it’s not inevitable but you also can’t reasonably predict which friendships are like the ones you describe that can survive a long hibernation and ones that for all the will in the world enter a freeze from which they never fully thaw.
No person nor source gets it right all the time, I like your idea as an evaluative technique but I think the assumption that being incorrect here is necessarily because of lying might mean discounting a lot of sources/creators who are otherwise reputable. I’d look at it more like degrees of doubt cast over everything else they say where you don’t have the expertise to evaluate the accuracy. Much like a driver’s licence, you get dinged enough times for more and more infractions and eventually you lose your license. If they keep continually getting things wrong where it’s something you know something about eventually you can probably discount them on anything else as well, but if it’s just once or twice, especially where they’re not egregiously wrong, some benefit of the doubt could be beneficial to all concerned. Better I would have thought to take what feels like their salient points on the content they produce on topics where you aren’t knowledgeable and check if other people are claiming anything similar and where something is verifiable, try to verify. Of course theoretically you should do that all the time but in practice at least each time you know someone is wrong about something it’s an indication that for them specifically further checking is required.