Does anyone else find it odd that 3 of the 4 vines are available again not long after you gather them, but that 4th one by the stairs takes f.o.r.e.v.e.r! I always check it and only once in awhile am I able to gather it. lol!

It might be bug.

I've noticed that, but I didn't think it was a bug. That vine might be a different species or perhaps the appropriate nutrients are available in that location. In any case, it seems to me there is no reason the vines should all have the same regen time.

When I gather vines at the three spots away from the waterfall, I always see them turn yellow. Any time I gather resources I see a visual change to depleted and a visual change to ready to gather. The vines at the waterfall do not turn yellow. This makes me feel like there is a bug, since they do not behave consistently.