If a physicsless part was attached to a winch, and then it got detached, it doesn't have physics ran on it. E.g. attach strutOcto to a winch. The winch will immediately trigger a refuse detach event. As a result of this action, the octo strut will become physicsless.

Alas, this bug is on the KSP side. The non-physical parts are supposed to get promoted to the physical ones via Part.PromoteToPhysicalPart(). Even though this method is properly called on the part decouple, the part doesn't become a proper vessel. It's out of the scope of KAS to address it.

KAS will emit a log record when this happens and won't attempt to auto-decouple in flight. Such parts can be removed from the winch via the stock construction mode. Btw, it won't work in KIS.

Well, a workaround has been found. It seems KSP fails to update the RB state on such parts. So, KAS will now be doing it. May not work in all the cases, though.