I don't know if it's isolated the Japan DLC or not since I haven't spent much time in the other locations much since the JP DLC release.
I've experienced visual frame glitches. For example, when casting it may skip part of the visual portion of that sequence. The best I can describe it is that it looks like a video that a few frames got cut out.
Yesterday, while single handed fishing, my "hands and reel" displayed as being over by my daughter while multi-player fishing...then they switched back to being in front of me.
I've also experienced a visual delay between feeling the fish take the bait and what the line and water look like. I can feel it in the controller, but don't see it at the water or line color. Again this happens infrequently and I have not been able to deliberately repeat it in order to report a specific sequence of events.