When you are building Nether Portals in the Upper World, if you build a second portal beyond the 2048 block boundary of the first, you end up with a completely different portal created in the nether for that block. This is fine and I am assuming normal. Now the distance between these portals in the Nether is MUCH smaller than the corresponding nether portals in the Upper World (somewhere around 1/8 to 1/10 the distance in the Nether). I am taking advantage of this and build Nether Portals in all neighboring 2048 block area so that I can travel between them through the nether. Traversing between portals in the Nether can be treacherous, but once safe paths are found or built, it is safe to move around at a good pace and go to a different portal to travel to the far away block on the Upper World. This all works great, except for one problem. My maps stop working correctly. For example, if I want to travel from my home base portal to the Nether and then move through the nether to the portal for the Upper World block immediately east of my home block, I enter the east Nether portal and end up where I am suppose to be on the Upper World, except my map still thinks that I am at the Upper World portal at my home base block. This is the case for the correct map for the east block (my new current location), which shows the 'out of range' square on the left border when it should show an arrow over the location of the Nether portal. I checked the 'F3' debug information and the system does know your correct location. The only way I have found to fix this is to completely shut down Minecraft and restart the game. At that point, the map in the east block now works correctly. As a software engineer myself, I recommend resetting the compass by default on all maps in personal inventory when leaving the nether for the upper world. That is apparently what happens on a cold restart. If this explanation is not clear, please let me know. Please note that the maps I use are all 2048 x 2048. Thank you.