On the PTR, there is a bug where the exit tile for the Dark Woods in the Underground Passage will sometimes not spawn. The reason as to why this may be is unknown.
The map seed that this bug was discovered on is 703599936.
The character file that this bug was discovered on can be downloaded here:
Naturally, since this is a PTR bug, you need the PTR to observe the bug. Without a PTR installation, downloading this file is worthless. This character has been hero edited for waypoints past the Stony Field as well as movement charms because I’m lazy. The file contains not only the .d2s file but a revealed automap of parts of Stony Field, the entire Underground Passage, and the entire Dark Woods. The file only has character save files (no executables), so you are at no risk of getting a virus.
Since the Underground Passage does not connect to the Dark Woods, the moment the game tries to load the tile that the cave leading to the Underground Passage is in in the Dark Woods, the game immediately crashes. The Dark Woods waypoint is directly next to this cave, so you crash the moment you load into the waypoint. You have to backtrack from the Black Marsh to enter the Dark Woods. The only area not revealed on the automap is where the cave is, and you will crash if you approach that area. I tried approaching on both D2R graphics and Legacy graphics, I crashed on both.
I tested both this character file and the seed itself on both the live D2R game and on LOD (legacy). The map generates correctly in those two versions of D2. It is ONLY the PTR where this issue is observable. Interestingly enough, the entire map is the same everywhere when comparing LOD/live D2R vs the PTR, with the exception of the Underground Passage. You can see in the following images that the format of the Underground Passage is similar, but different tilesets are used in some locations.
Here is an image of the full automap on PTR:
Here is an image of the full automap on live D2R:
and an image of the full automap on LOD:
I’ve shown this bug to a few D2 community members knowledgable in the game’s code from LOD, and one suggested that it’s possible some tiles that were unfinished/not in use in the original game were somehow activated in the PTR. There is no testing basis behind this though, simply an observation. Maybe helps as a potential lead for developers.