It may well but, but everybody knew that GDPR was coming. If this was the reason, why not announce it (much) earlier?

At first, I immediately discounted it as just plain coincidence. But actually, it could well have been.

I imagine the service wasn't really making money, and to add GDPR compliance on top, could have been the last straw (or a contributing factor)

I am thinking that it sets them up to announce something (possibly fully embracing K8s) at DockerCon[0] which is a few weeks after.

0: https://2018.dockercon.com