Clarifications on user_first_touch_timestamp and previous_first_open_count in first_open Events

[manhl]

My understanding is as follows:

• user_first_touch_timestamp: Represents the first interaction of a user with the app.
• event_timestamp: Indicates the specific time when the first_open event occurred.
• previous_first_open_count: Shows the number of previous installations on the same device or associated with the same pseudo_user_id.

However, I've noticed some discrepancies that I'm hoping to understand better:

1. I observed instances where, for a pseudo-user, the first instance of a first_open event comes with a previous_first_open_count greater than 0. Why is this possible?
2. When a user switches to a new device, the new first_open event seems to carry over the same user_first_touch_timestamp but restarts the previous_first_open_count from 0. What might be the underlying logic?
3. Following the second point, similar behaviour is observed for user using the same device.