PORTURBAN maps aren't used anymore on the latest version of the Terrain Pack/Area 51 (been replaced with the PORTUFO maps). On MUJUNGLE03 I found a bad node on a location not mentioned on the list above.
These are not from terrain pack/area51 though... I mean, originally yes, but they've most likely been changed by others until they got into piratez, where I took them from.
Also, Solar has been fixing them recently, that's why you could have found something that wasn't listed, as one possible reason.
I've downloaded latest area 51 now and this is the result I got:
EDIT: removed duplicates from the list
Bad node in RMP file: ROUTES/ISLANDURBAN12.RMP Node #3 is outside map boundaries at X:254 Y:5 Z:3. Found using OXCE+ test cases.
Bad node in RMP file: ROUTES/MUJUNGLE03.RMP Node #2 is outside map boundaries at X:255 Y:255 Z:3. Found using OXCE+ test cases.
Bad node in RMP file: ROUTES/MUJUNGLE03.RMP Node #3 is outside map boundaries at X:255 Y:7 Z:3. Found using OXCE+ test cases.
Bad node in RMP file: ROUTES/MUJUNGLE03.RMP Node #4 is outside map boundaries at X:255 Y:255 Z:3. Found using OXCE+ test cases.
Bad node in RMP file: ROUTES/PORTUFO05.RMP Node #7 is outside map boundaries at X:255 Y:5 Z:2. Found using OXCE+ test cases.
Bad node in RMP file: ROUTES/PORTUFO21.RMP Node #30 is outside map boundaries at X:20 Y:11 Z:1. Found using OXCE+ test cases.
And from what I'm seeing on MapView, it seems technically impossible for .MAP/RMP files to have dimensions of 255x255, so I have doubts if the info listed above about the coordinates is correct.
I'm pretty sure this time, but I'll double check anyway.
And if the file is corrupt, there's no reason why the coordinates could not be 255, it's represented by 1 byte in the file, so anything between 0 and 255.
Also, if for example X:20 doesn't seem suspicious, on 20x20 map block you should have only X between 0 and 19.