I would hesitate to comment on the structural integrity. But knowing the flaw is there would always bother me. If it does fail, the seat post will slide down suddenly. Crash material. Probably not but I do know that I would never trust it.

Were it me, I would want, at the very least, to remove the paint and take a really good look at what was going on. Repair might be pretty simple but kiss the paint goodbye. Nice bike and, needless to say, that Bianchi green is super duper, in my mind.