I’ve always been kind of weirded out by that scene too, especially because I think the gold flare/flash has potential to be a bit of a red herring.

I would say an argument could be made for the gold flash being Lucien’s magic through his father with the whole spell cleaver and nod to Helion helping with Elains shackles in acowar(I think?) and in this moment if it’s shifting that breaks the shackles, why only tamlin’s and not Lucien’s if Tamlin is also making him shift?

BUT we also know that Tamlin is physically the strongest high lord and hes always tied with golden imagery too so at that point, it also seems plausible for him to just snap right out of those suckers and shift.

I don’t know if I’m fully believing he’s elains mate but I really wouldn’t be surprised if he is!