The only way I can see this working is if they messed up and put IASA frames (interruptible as soon as) near the end of the move, but forgot to put in an ending autocancel window or put it way too late and after the IASA, which considering you ALWAYS seem to lag from this move unless it's 100% over I can see it not being autocancellable at all.
If you go offstage with this move, can't you jump out of it earlier in it than when you would need to wait until landing with it when doing it on the stage to not lag? That would mean it is IASAable, and if that's before the AC window if that even exists, then this makes sense as long as you can IASA stuff with airdodges.
Normally the AC window should start before you can IASA it, so by the time you could airdodge you could just land anyway and the autocancel would make you land without the attack's lag. If they didn't program in that AC window though, IASAing it would be the only way to avoid getting the lag without needing to complete the full duration of the move.