[2019] My islands are not saving properly, every time I load, or rejoin, I lose stuff.

I've been working on making a little swimming hole with all sorts of nifty little spots, like caves, jumping spots, a meteor underwater you can swim through, etc, and I've been working pretty hard on it, however, whenever i need to reload or rejoin, I lose a lot of progress, I just finished the terrain part of the swimming hole, and was about to start decorating but the storm was moving in, so I reset the game, when I joined back, almost all of my work was gone, but the props I had just thrown down were there, this is really frustrating because I keep having to redo things and its not the same the second time. :(

Is anyone else experiencing this? Are there any remedies?