I just received my Form 3 last week. On my 3rd print I found this cover and gasket sitting inside the resin tank. It seems that it blew off the build plate during printing. I’m assuming the heat built pressure inside the build plate cavity and pushed it out. I think I need a new build plate and possibly a new resin tank as it may have been scratched due to the cover being inside the tank while printing. Please let me know how to proceed.
Definitely open a ticket with Support. I imagine they’ll ship you a replacement build platform. They’ll probably also get you to drain the tank (ideally through a paint strainer) and inspect it for any damage.
Unofficially, depending on the condition of your existing build platform it might be salvageable. I’ve taken them apart and put them back together before. Some users have even filled them with self-expanding foam or sealed them with silicone caulk to make them more robust and prevent resin seeping in through the cracks and back out later.
Rest assured what you encountered isn’t common (at least as far as I’ve seen).