How to reproduce:
1. Open user's attached project "ID.zip"
2. After the project is loaded wait from 10 to 15 seconds and the project will crash

Expected result: User can modify the project through Editor
Actual result: Unity crashes

Reproducible with: 2018.2.0f2
Not reproducible with: 2017.2.3p2, 2017.4.7f1, 2018.1.9f1, 2018.3.0a1, 2018.3.0a5

Note: Majority of the time the crash is reproducible. Sometimes to reproduce the crash you will need to close and open the project a few times. I have attached Editor.log, crash.dmp and error.log files in the description below

First three lines of the stack trace:
0x00007FFFCFCD4687 (mono) [f:\dd\vctools\crt_bld\SELF_64_amd64\crt\src\amd64\memset.asm:148] memset
0x000000000073CED4 (Mono JIT Code) (wrapper managed-to-native) System.Array:ClearInternal (System.Array,int,int)
0x000000000073CDC8 (Mono JIT Code) [/Users/builduser/buildslave/mono/build/mcs/class/corlib/System/Array.cs:910] System.Array:Clear (System.Array,int,int)