Sorry I’m late to this thread, but I would bet that you used the inflate brush to push *inward* with Subdivide edges mode. That consistently causes these kinds of artifacts in my experience. As a rule of thumb I only use Subdivide collapse when inflating inwardly. That method auto-generates new topology as you go and prevents the “collapsing in on itself” artifacts.
Thanks to @spikeyxxx and @blanchsb for the help on this one!
