Creating a specific topic for this problem so that a resolution and/or workarounds can be shared.
The original exchange can be found here: https://devtalk.nvidia.com/default/topic/1019640/jetson-tx2/jetpack-3-1-mdash-l4t-r28-1-released-for-jetson-tx1-tx2/post/5210354/#5210354
It was first publicly documented in the R28.1 release notes:
http://developer2.download.nvidia.com/embedded/L4T/r28_Release_v1.0/Docs/Tegra_Linux_Driver_Package_Release_Notes_R28.1.pdf Page 13.
When configuring the wireless card to operate in Ad-Hoc (IBSS) mode using encryption WEP or WPA, the system would crash. However, if configured to not use an encryption key the Ad-Hoc mode would work without crashing.
The problem was not present on the previous JetPack driver release (27.1) and TX2 units running R27.1 can utilize all supported encryption modes while in Ad-Hoc (IBSS) mode.
Unfortunately, some carrier-board support packages require R28.1 so it is not possible to revert to 27.1 to get around this problem.
If there are any updates on a solution, please share them here.