Steps to reproduce:
1. Try to get a horse/pig (any mob you can ride) on the boat.
2. Row the boat, while at the same time, try to mount on said rideable mob.
3. What should happen is that you will be kicked off the boat, and said boat will go on autopilot in the direction it's facing with the mob on-board.
Thank you for your report!
However, this issue has been closed as a Duplicate of MCPE-12078.
It has been linked to this report. If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Feedback – 📖 Game Wiki