This has been a known bug of Eclipse Neon for some time.
If you are having stability, that’s good, although Eclipse Neon is not guaranteed to be stable on 10.13 or 10.14. If you find that the instability re-occurs, the only real fix is to install Eclipse Oxygen, and then install SystemWorkbench from within Eclipse. Unfortunately, this is a suboptimal solution as the debugger isn’t fully functional.
So we will need to wait until OpenSTM32 group migrates to Eclipse Oxygen for full stability and support.