Challenge Island: Trade Routes

[hoshisabi]

I'm having problems with Trade Routes, on winter island, over time the berry bushes stopped allowing me to spend a coin to replenish them. It makes it next to impossible to earn enough coins, it was just one bush at first which was livable, but now I have resorted to making quick trips back to summer to get coins, and just now... I can't board the boat again. I have the ten coins I need to do so, but ... Nope.

I hate having to restart AGAIN, especially since I don't know if it's not just going to bug out again and never let me complete.