Reproduction steps:
1. Download and open the attached project: "test-project.zip"
2. Go to Assets > Test 1 and open the PlaymodeTest script with Rider
3. Add a breakpoint at line 19
4. Attach the script debugger to the Editor
5. Run the debugger
6. Once it hits the breakpoint, detach the debugger

First 5 lines of the stack trace:
0 0x007f4677044980 in funlockfile
#1 0x007f4676c7ffb7 in gsignal
#2 0x007f4676c81921 in abort
#3 0x007f44f100d8d9 in monoeg_assert_abort
#4 0x007f44f0ff6e1a in mono_dl_fallback_unregister

Reproducible with: 2021.2.0a18, 2021.2.0b7, 2022.1.0a5
Not reproducible with: 2019.4.29f1, 2020.3.16f1, 2021.1.17f1, 2021.1.17f1

Notes:
- Not reproducible on Windows and macOS
- Tested with Rider 2021.1.5 on Ubuntu 18.04
- The issue can be somewhat inconsistent and require a few tries for the Editor to crash