Reproduction steps:
1. Create a new project
2. Add Entities package through the Package Manager
3. Import the attached script ("BuggySystem.cs")
4. Enter Play mode and observe Console

Expected results: At first the boolean variable is false and all following printed values of it is true
Actual results: Boolean is false, inside code block after a ForEach it's assigned true, but out of the code block it's false once again

Reproducible with: Entities 0.6.0-preview.24, 0.11.0-preview.7, 0.11.1-preview.4 (2019.3.16f1, 2019.4.2f1, 2020.1.0b14, 2020.2.0a15)
Didn't test with older Unity versions since the package versions with which the issue is reproducible are unavailable in those streams. Couldn't test with older package versions due to code-breaking when downgrading

Notes:
- Package found version is the first package version with which the code in question could be run without any errors
- In this case the code in question is in a class which is derived from SystemBase and is executed in an overridden OnUpdate() method