I was playing through the campaign mission "Off-World Recovery" and accidentally fell through the top of the rock outside the Hallowed Grove lost sector in the EDZ. It seems there is at least one point where the rock is missing its collision, which lets you fall through if you find that place. I linked a video demonstrating the place I found. While it doesn't impact a lot gameplay-wise, it's still something that someone else might stumble on while playing.
Steps of reproduction:
1. Travel to the European Dead Zone, either in the public instance or through a campaign mission that goes to the Hallowed Grove, such as "Off-World Recovery".
2. Progress to the entrance to the Hallowed Grove lost sector.
3. Jump onto the rock with the Lost Sector symbol on it.
Expected behavior: The rock is completely solid: on all surfaces you can either stand on it or will fall down the outside.
Actual behavior: On at least one spot (near the top of the rock to the right of the lost sector symbol is the one I found) the rock is not solid, allowing someone to fall into it.
Machine and build-specific details
OS: Windows 10 (10.0.18362.535)
Processor: Intel i7 4770K
GPU: Nvidia GeForce 1070 (Driver version 411.66)