Not sure if anyone else experienced this, but I noticed that if I do the quest at the Hagar settlement to get the Evenflow 2x boost by doing the dunebuggy time trial, when the race is completed, my Wasteland ATV disappears. (This is the one with the cow skull on the front.)

I have tried parking it in various locations and no matter where I park it, it always disappears when I do this quest.

The original ATV (the one without the skull) does not disappear. Personally, I prefer driving the Wasteland ATV to the dunebuggy, so I hope there is a way to resolve this.

I don't think this has anything to do with my hardware or drivers, but in case it's helpful, here are my specs:

specs:
hp envy 15 laptop
i7-820QM 1.73GHz (3.06GHz turbo)
1GB AMD 5830m (running at stock clocks)
16GB DDR3 RAM
Dual Intel X18 G2 SSDs in Raid0
1920x1080 display

Steam launch options:
+set com_skipIntroVideo 1 +set com_allowConsole 1 +fc_maxcachememoryMB 1024 +ik_enablesmoothing 0 +image_usecompression 0 +m_smooth 0 +m_rawinput 1

Rageconfig.cfg tweaks: None

Catalyst Control Center settings:
AA: use application settings
AF: use application settings
Tessellation: use application settings
Catalyst A.I.: "Advanced" mode
Mipmap Detail Level: Slider maxed at High Quality
Wait for vertical refresh: Always on
AA mode: Performance / Multi-sample AA