Water-route technique
Redirect the current before launching the lily pad
If the pad keeps taking the wrong river, check the water before changing the pad. Some stones prepare the current; another stone supplies the launch.
The short answer
Make the required stone collision in the water, inspect the changed downstream path, and only then launch the pad into it. If the current still has its original shape, repeating the same launch will repeat the wrong ride.
The pictured examples come from launch demonstrations, not an October 15 playthrough. Match the islands and prepared objects before using an exact route; updated checkpoints or layout details may differ.
Example 1: open the eastern-checkpoint route
In the horizontal-current board, first use the two stones near the central pale island to create the upper collision. In the launch route, move the lower stone up twice, right, then up into the stone above. This is the water-changing step.
Do not spend the other stone as an improvised repair. It is the pad launcher. If the islands or prepared stones differ, compare the board directory before applying the exact sequence.

Read the new route, then use the launcher
After the diversion, the same board’s other central stone moves right, down twice, then left to send the pad upward. Ride the adjusted stream to the eastern checkpoint. The useful result is access to that bank, not simply a pad floating in a bright stream.
If it loops past the bank, undo the launch and inspect the upper collision and water path. Keep the water-preparation job separate from the launch job. Use the linked board route for the later southern bridge or treasure detour.

Example 2: divert west, then ride north
In the west-current home loop, the upper island first provides a pushing position. A stone is sent left into the water; a second stone collides with it to change the western flow. Only after that does the remaining stone launch the lower pad left into the adjusted current.
Check that the ride goes north to the upper checkpoint. If the pad enters the old straight current, the diversion is incomplete. Undo the launch, repair the collision, and then retry; do not keep launching into unchanged water.

A failed diversion versus an incompatible old save
During an ordinary attempt, an unchanged stream usually means you have not completed the specified collision. Compare the prepared stones and undo the incorrect action.
A different case was reported after October 14: currents reset while stones stayed where players had put them. The October 15 level-version fix can clear partial progress in the first level. If that is your situation, follow the update-and-replay guidance rather than spending more stones on a water state the old route was not designed for.
Check your result
The water path has changed before launch, and the launched pad reaches the intended checkpoint bank rather than repeating the old route.
Sources and version details
Follow the linked demonstrations for the complete pictured routes.