1) While booking, the booking status was WL/Available.
The max booking status had gone up to WL 3 and due to some cancellations, berths were available.
This was the time when you had booked the ticket.
2)...
more... While booking, the current status was WL 3 and just after you booked or in these few days, some tickets were cancelled and hence your berth got confirmed.
Here Confirmed means that you have got a confirmed berth, and WL 3 signifies your booking status.
Similarly, if the current status at your time of booking would have been WL 1, then the Confirmed portion in the PNR would have been replaced by WL 1 and the rest would remain same.
If the ticket says:
Passenger 1: Confirmed (Booking Status: W/L 3, GNWL)
then situation 1 would apply
If the ticket says:
Passenger 1: WL X (Booking Status: W/L 3, GNWL) [Here X<=3], then situation 2 would apply.