If the music stopped now, the absolute level of long-end yields for many issuers looks reasonably fair. The problem is the music is still blaring. A lot is going on, and most of the pressure continues to point upwards for long rates. That does not have to be a drama, but then again, it could become one should it get pushed too far
It can take a lot to awaken long-end yields, but when they get prompted into action, they can be quite flighty. We've seen various episodes of this in recent years for idiosyncratic reasons. Think UK gilts and French OATS and respective political post-pandemic wobbles, or the perception of joint liability attached to Italian BTPs and concern there pre-pandemic. The past number of months have been different, as we've seen a synchronised rot attach to long ends, in particular across many (or most) developed markets.