"m_ResourceToKeyMap.find(tid) == m_ResourceToKeyMap.end()" exception is thrown on changing color space Linear to Gamma.

Steps to repro:
1. Create a new Project with LWRP template.
2. File > Build Settings > Player Settings.
3. Other Settings > Uncheck "Auto-Graphics API for Window" checkbox.
4. Add Direct3D12 > move to the top of the list > Apply.
5. Change Color space Linear to Gamma.

Actual Result:
"m_ResourceToKeyMap.find(tid) == m_ResourceToKeyMap.end()" exception is thrown in the console.

Expected Result:
No exception is thrown in console.

Reproducible in:
2019.2.0a4, 2019.1.0b2, 2019.1.0a14, 2019.1.0a10.

NOTE:
1. LWRP option is available in the template Menu from 2019.1.0a10.
2. It occurs with only DX12.

Environment:
Occurs only on Windows.