When the warp return used for a tile or side warp is changed, the warp return used for the other type of warp is also changed. Ex: If I set tile warp A to use warp return C, then side warp A is also set to use warp return C. Same goes if the side warp's warp return is changed.
[RC1] Warp return setting for Tile/Side warps
I'm not entirely sure this is actually a bug. But despite this rather annoying behavior, I've been able to arrange the tile warps/side warps so that they use the warp return points I want them to use. It may be tricky, but you just might be able to figure it out somehow.