> having worked for the last 12+ years as a developer to be told that there were "concerns about your technical competency"

Oh yeah I've had a couple of those as well.

Usually because you can't remember one detail that can be googled or is opinionated about one specific aspect.

At the end I guess in some companies it's more of "who can jump through the hoops like a nice circus animal" more than anything.

(On the opposite side, if you throw me fizzbuzz I'll just make it harder on purpose)