How to reproduce:
1. Open the user's attached "VS2019DebuggingIssues" project
2. Open the "DebuggingScriptTest" found in the "Assets" folder
3. In the script uncomment the 36th line and add a breakpoint in line 49
4. Attach the script to Unity (by pressing "Attach to Unity" with a green triangle at the top of Visual Studio)
5. In the Editor enter the Play Mode

Expected results: The breakpoint is triggered
Actual results: The Editor continues playing, the breakpoint isn't triggered

Reproducible with: 2018.4.29f1, 2019.4.15f1, 2020.1.15f1, 2020.2.0b13, 2021.1.0a7

Notes:
- The string that causes this issue is "<AutoExecFile param="{d3droot}\Cfg\CrossConverter\CrossConverter_Multilateral.xml"></AutoExecFile>", deleting any part of this string fixes the issue (there're two of these strings in the "config.xml" file, lines 9 and 10)
- Adding this string directly after fixing it (adding \ before other \ and " symbols) instead of as an XDocument variable converted to a string will not reproduce the issue
- The issue does not reproduce with Visual Studio 2017
- After entering the Play Mode you can attach the script to Unity and the breakpoint will be triggered