preact: inconsistency during unmount

Hey, there is an inconsistency during componentDidUnmount, most of the time this.nextBase is populated but sometimes this.base will and this.nextBase is null

don’t have a repro yet, it happens in many places in my app and in different components

could be the cause of this is similar as the one that prevented me from using any version from beta19+

will provide a repro if I manage to figure out how to break it outside of my app