this bug happens when I re-switch to minecraft after having switched to a different tab (e.g. browser). The game freeze for a few second, then crashes.

The thing is, while the crash is happening, it seems like the games saves, but in a weird way. The player inventory saves as intended, but the world data (blocks placed) don't save. This is a huge problem, as, if I placed a rare block or a shulker box full of items on the ground a few moment before the crash, when the game crashes, the game saves my inventory (rare block is deleted of my inventory in the save file), but as the blocks placed don't save, the block isn't saved in the chunks data, so, when I open the world after re-opening the game, my precious block is gone forever.