[BUG] TransportLinesManager crashes CS when trying to save game

[CelestialMaege]

Describe the bug
When trying to save a game (happens both with a new game or previously saved game), with TransportLinesManager enabled Cities: Skylines crashes (it disappears/closes while Steam still says it's running) immediately after setting save name and clicking save. The game is not actually saved so any changes are lost.

This took some testing to isolate TLM as the cause. Tested with
-no mods (saves fine, no crashes)
-a number of other mods enabled (saves fine, no crashes)
-other mods + TLM enabled (CS crashes when trying to save)
-vanilla CS + only TLM enabled (CS crashes when trying to save)

To Reproduce
Steps to reproduce the behavior:

1. Enable TransportLinesManager
2. Open a new or previously saved game
3. Try to save the game
4. See error

Game Logs
player.log
Player.log

Screenshots

Additional context
Running on Linux. Disabling TLM mod allows CS to save fine again and no crashes.