I think the game is bugged for me. Noticed numerous negative glitches, but one keeping me from completing...

I think the game is bugged for me. Noticed numerous negative glitches, but one keeping me from completing. I've opened 3 (the max I think) islands in each biome, but "cant fix" the bridge to the last. There's A quest saying I need 5 crab shells and 5 iron ore for it. Quest is completed, take resources to the broken bridge - - nothing. Still says "can't fix yet". I've done everything I possibly can to this point.