I was building at nether, creating paths between my portals. Finished the job, took a step back to admire. Then proceeded to go back to my base with a portal. I went, grabbed some blocks, went back to nether and all the progress I've done in 4 hours is gone. Lost all my shulkers too since they were on the ground. Went off, decided to do some end city raiding, emptied my ender chest and gathered a few essentials. Went to end, had a great time and gathered some decent loot but died to void when my elytra broke. I spawned back in my base, went back to grab a back up gear from the shulkers I've removed from my echest, surprise surprise they're gone too. The 30 minutes-ish base organization progress too. So basically game revamped the work when I've left the dimension. Idk how but it costed me about 90% of my progress in this soon to be 2 years old world. The world doesn't save when you leave it and just reload the latest or something like that. Because it wasn't really old, like 5 minutes before I've started working, or removed the shulkers. But they're gone. About 40 shulkers full of my stuff is gone. Reporting so it won't happen to others again