-Does the door always go back down after the relay opens back up, or only sometimes?
Yes, it behaves this way every time.
-Does it ever "false start", that is to say, try and fail to open at the beginning?
No, it begins to open the door every time, no false starts.
-Can you paint me a more detailed picture of what your setup looks like? It's a lot easier to debug a system with a schematic in front of you, but words work too.
It's very simple in terms of the setup... the mechanical button that is used to open/close the garage door is basically a momentary switch (normally open, completes circuit when pushed). The relay is wired directly to the same two posts on the garage door opener that the mechanical switch is.
-Have you tried using the relays from the Pi with Tessel? Since both devices use 3.3V GPIO, you should be able to connect the Pi's hardware without too much difficulty.
Actually, on the Raspberry Pi I am using the equivalent of a solid state relay made using a PNP transistor that a friend of mine made. I have not tried it with the Tessel yet, but I would assume it would work just as it does with the RPi.
Additionally, the HTTP server has proven to be too unreliable on the Tessel so this project will be delayed a bit while the bugs are still getting ironed out of the Tessel software.
I read a bit about "contact bounce" at it is my assumption that is the issue I am having... I'll respond when I get back to this project and have a little more detailed info.
Thanks for your help.