So, naturally, I was able to reproduce it on the first attempt..lol. Here's the sequence I used:
1. Starting from standing in the shelter at my settlement I walked on the strategic map to the shelter on the river and dropped to the tactical map.
2. Moved to the raft, picked up the paddle, used 'A' to wield paddle, moved out straight east 16 moves into deep water and fished. The time was the small hours.
3. I fished until noon, catching not one damn fish!
5. Moved directly west, back to the shore. I dropped the paddle on the raft and moved to the strategic map while standing ON the raft.
6. I moved south to check the traps there, then returned to my settlement.
7. I picked up some food from my cellar and then a spent some time stealthily stalking a glutton that had come into view. Eventually, he took the bait on a deadfall and I skinned and butchered him.
8. Returned to the river shelter site on the strategic map and the raft was on the strategic map again. I saved again at this point if you want it.