To reproduce:
1. Open any project
2. Import my attached script (INVALID_UTF8_TEST.cs)
3. Select it in Project window
4. In Inspector window, observe your selection

Expected: symbol is recognized
Actual: symbol is not recognized

Reproduced in: 2017.4.12f1, 2018.1.9f2, 2018.2.11f1, 2018.3.0b4, 2019.1.0a3

Note1: on 2017.4, 2018.1, Inspector window shows empty description field
Note2: failed to reproduce on a newly created script (copying or alt-coding the symbol to the script)
Note3: according to user, this causes problems with certain Unity features such as Timeline that are then unable to match the script name with the filename