How to reproduce:
1. Open user-submitted project (BugReport_PackedMemorySnapshot_NET4_Scripting_Runtime.zip)
2. Click "Mainmenu > Edit > Project Settings > Player and expand the "Other Settings" tab
3. Change the "Scripting Runtime Version" to .NET 3.5
4. Open open "Bugreport" > "TestCode Window"
5. Click "Capture Memory 'Editor'"

Expected result: Captured Memory Snapshot contains information about variables in the Snapshot
Actual result: Captured Memory Snapshot is missing some information about the variables in the Snapshot

Reproducible with: 2017.4.11f1, 2018.1.9f2, 2018.2.8f1, 2018.3.0a3
Not reproducible with: 2018.3.0b1

Note: Reproduces on all OS'es(Ubuntu 16.04 Ubuntu 18.04, OSX, Win10, Win7). The issue is fixed in 2018.3.0a4.