No, this is not normal at all.
Can you check this ?
- Reboot
- Launch FSX
- After it loads the initial screen, quit FSX
- Open Task Manager, verify that both FSX.EXE and Couatl.exe processes quit.
- If FSX.EXE has closed and Couatl.exe hasn't, wait a little bit more
- If it's still running, then something must be wrong. You can, however, manually Terminate it, before launching FSX again, so it will not create another process.