Originally Posted by PatriceJ

two adapters in a row?
i hate to ask this question, but it must be considered:
are you absolutely sure you are attaching the adapter properly and securely each time?

i'd been using my 8900 for many months when i suddenly started experiencing a weird problem that happened only when i was using the dual feed adapter and feet. i had made up my mind to take it in for warranty examination and repair. as suddenly and mysteriously as it started - it stopped happening. everything has been hunky dory for the many months since then. soooooo ... the virtually inescapable conclusion [in my case] is that i must have been doing something wrong when installing the adapter.

when you pick up the next adapter, haul your machine in, too. have the dealer watch while you install it.
also ask your dealer to give your machine a thorough examination to ensure all of the machine parts are working properly - with [naturally] emphasis on examination of the parts involved in attaching and holding the adapter in place.