According to the patch
- Fixed the issue where the fishing chair appeared unnatural when the character stood up after attempting to fish in the air.
- Fixed the issue where another character's fishing chair sometimes appeared unnatural after loading ended.
To your credit these bugs at least "seem" to be fixed. Unfortunately, now using the new Manos Fishing chair, I seem to be bugged, so that my own chair is not in the right spot.
In the screenshot below that is me with no chair under me, but instead it is flying in the air behind me. I have tried unequiping and reequipping the chair, and restarting the whole fishing process, but I am stil bugged. I finally swapped characters back and forth yet and that did seem to fix the issue. At least for now.