Nether rebuilds itself upon leaving and reentry

Upon entering the nether and performing a lot of work, Left nether for a while and came back. Upon reentry was placed in a random location in the nether nowhere near the coordinates it should be, With NO portal. walked back to the location of the original portal to find all the work gone and no portal. Had to go into creative to build a portal to get out. Every time any work is done in the nether, upon reentry its all gone and reverted to original nether. Also on side note, Lava without source block

-Only one nether portal open in the server
-Server settings besides ram usage have not been modified

• Happens WITHOUT a reboot while still live