

A loose fitting came off
Ask him if he recalls tightening and making all the fittings. (From automotive, any bolt that gets torqued gets paint marked when torqued. At least in my garage)
no matter what he says. Just say one was left loose and you don’t recall who did it, but it wasn’t marked so be sure to mark in the future.
Note, this marking can save you as well, if someone takes it onto themselves to play, you can point out the broken paint and reject warranty work








I find it ironic there’s no period in your post either.