Sharing trainer with others

Hi All

I am asking you about your experience. Do you have any tips, tricks, information about sharing one trainer by two users?

Today I started my season with trainer and after my ride my friend used the same trainer with the same bike but with another tablet with other Garmin account. My ride was okay, no issues observed. His ride showed abnormal speed compared to his effort. It was definitely too easy to jump to 30kph - even after new calibration.

After his ride I saw that he had set his bike (by default) as triathlon bike instead of mountain bike. That was the only difference in our settings (excluding body weight)

I am confused and I do not know if I missed something or is it any resolution for this?

I would be grateful for your answers