Steps to repro:

1. Open attached project on OSX;
2. Open the Lighting window (Windows>Rendering>Lighting Settings);
3. Click 'Generate Lighting' button.

Actual result:
Editor crashes with an empty stacktrace without bug reporter. See attached video.
Regression introduced in Unity 2018.3.0a2.

Crash is accompanied with the following assertions:

[PathTracer][LP] Light probes 0690454dd9f5542c6878a3eedfba7d0e render -> fired: 57.67 krays in 1.17 secs (49.46 krays/sec), pass: 0, converged: false [72.602 - 73.768].
Assertion failed on expression: 'maxGISamplesPerPass >= 0'
0 Unity 0x00000001018cb9ec _Z13GetStacktracei + 92
1 Unity 0x0000000100189bdb _Z17DebugStringToFileRK21DebugStringToFileData + 795
2 Unity 0x00000001017598d0 _ZN24BakeJobRenderLightProbes7ExecuteEPb + 416
3 Unity 0x00000001016cf752 _ZN17PVRContextManager14UpdateFunctionEPv + 594
4 Unity 0x0000000100bf1a37 _ZN8JobQueue4ExecEP7JobInfoxi + 359
5 Unity 0x0000000100bf18a5 _ZN8JobQueue5StealEP8JobGroupP7JobInfoxib + 997
6 Unity 0x0000000100bf25e1 _ZN8JobQueue19ExecuteJobFromQueueEv + 97
7 Unity 0x0000000100bf27d6 _ZN8JobQueue11ProcessJobsEPv + 214
8 Unity 0x0000000100bf0bd7 _ZN8JobQueue8WorkLoopEPv + 279
9 Unity 0x0000000100e329ec _ZN6Thread16RunThreadWrapperEPv + 60

and

Assertion failed on expression: 'giSamplesPerPass >= 0'
0 Unity 0x00000001018cb9ec _Z13GetStacktracei + 92
1 Unity 0x0000000100189bdb _Z17DebugStringToFileRK21DebugStringToFileData + 795
2 Unity 0x0000000101759a7d _ZN24BakeJobRenderLightProbes7ExecuteEPb + 845
3 Unity 0x00000001016cf752 _ZN17PVRContextManager14UpdateFunctionEPv + 594
4 Unity 0x0000000100bf1a37 _ZN8JobQueue4ExecEP7JobInfoxi + 359
5 Unity 0x0000000100bf18a5 _ZN8JobQueue5StealEP8JobGroupP7JobInfoxib + 997
6 Unity 0x0000000100bf25e1 _ZN8JobQueue19ExecuteJobFromQueueEv + 97
7 Unity 0x0000000100bf27d6 _ZN8JobQueue11ProcessJobsEPv + 214
8 Unity 0x0000000100bf0bd7 _ZN8JobQueue8WorkLoopEPv + 279
9 Unity 0x0000000100e329ec _ZN6Thread16RunThreadWrapperEPv + 60

Notes:
- Reproducible un 2018.3.0a2;
- Not reproducible in 2018.3.0a1, 2018.2.0b9, 2018.1.5f1.
- Reproducible only on MacBook Pro with OSX 10.13.5; not reproducible on Windows 10;
- Crash is not reproducible after clearing GI cache/baked data and rebaking - in this case only assertions are displayed and baking is stalled;
- Crash doesn't happen when baking with Enlighten, it only happens when baking with PLM;
- Crash doesn't happen without light probes.