Steps to repro:

1. Open the attached project (from the comments section);
2. Open 'ProgressiveLightmappingExample' scene;
3. In the Lighting window press 'Generate Lighting' button;
4. When the baking starts select Assets>Recompile Lightimapping Shaders.

Actual result:
Errors:
`OpenRL reported error code 502: OpenRL error occured: RL_INVALID_OPERATION: Too many output rays emitted from program 'DefaultVertexShader:Standard'. (rl_CurrentPrimitive = 9ea66c3e13281928d27bbfcf0c7e3da8:0; rl_InRay.class = 0; rl_OutputRayCount[0] = 17)

RtlLookupFunctionEntry returned NULL function. Aborting stack walk.
0x00007FF77C5FE5BC (Unity) [stackwalker.cpp:963] StackWalker::GetCurrentCallstack
0x00007FF77C601A91 (Unity) [stackwalker.cpp:942] StackWalker::ShowCallstack
0x00007FF77AC7F6D5 (Unity) [stacktrace.cpp:140] GetStacktrace
0x00007FF77D140F90 (Unity) [logassert.cpp:1026] DebugStringToFile
0x00007FF77CF0A9A9 (Unity) [pvrcontextmanager.cpp:89] PVRConsoleMgr::ErrorPrintString
0x00007FF77A98C1B2 (Unity) [consolemgr.h:83] Wintermute::ConsoleMgr::Print
0x00007FF77A98C27C (Unity) [contextmgr.cpp:70] Wintermute::ContextMgr::RLErrorCatcher
0x0000000180005ADF (OpenRL) [rlcontext.cpp:296] RLContextTriggerError
0x0000000180005C3B (OpenRL) [rlcontext.cpp:103] RLContextMCNotify
0x0000000180024443 (OpenRL) [maincontext.cpp:520] MainContextRaiseError
0x000000018002ECB6 (OpenRL) [rterrors.cpp:155] _RTError
0x0000000180087952 (OpenRL) [zipshading.cpp:743] DisplayOutputRayOverflowError
0x000000018006641B (OpenRL) [zipshading_sse.cpp:342] ZipShadingRuntime_EmitRayWithoutDifferentialsSSE
<Missing stacktrace information>
`

are shown in the Console. See attached video and Editor.log file.

Expected result:
Lightmapping shaders are recompiled without errors.

- Reproducible only in lighting/recompile-shaders-crash, that fixed a crash when recompiling lightmapping shaders;
- Reproducible on Windows and OSX;
- The issue reproduces only with CPU Lightmapper;
- The issue doesn't influence the bake in any case.