That is a terrifying video but is basically what happened to me.
So I chucked the bike on the turbo, the chain is jumping obviously now. 800 watts can get it to jump indoors. Here are two videos from below and the side.
Checked the front mech and it isn’t touching the chain at all when still. Bike is an orbea orca aero.
Chain was sized with park tools big 2 big method. I could probably shorten it 1 more set of links but it is already pulling the rear mech a lot when crosschaining. Checked b limit screw that looks in spec. Really confused now.
Excuse the baggy work clothes and messy floor 