By default, the symptoms tracking was "Enable" to all companies. To turn on/off, you have to go to the company settings. Below are the steps:
1) Tap on the company icon to enter the Company screen.
2) Scroll down and search for "Other" at the Settings category. Tap on it.
3) Toggle on to enable it, while toggle off is to disable it. The changes would be automatically when you update the setting.