I got some extra(more than 3) rated puzzles even i am not premium member

Puzzles that have a "pending" rating do not count towards your daily limit. The algorithm is trying to determine the appropriate rating for a puzzle so it would be unfair for it to count towards your daily limit. Additionally, you don't lose points if you incorrectly guess a "pending" puzzle (you receive +1 for incorrect answers).
Hope this helps

Can you pls tell me what exactly do you mean by pending rating
I can't find an example at this moment, but after you finish a puzzle look at the rating. If it doesn't have a rating yet, it will say "Pending".
But I somehow still managed to get more puzzles to do than the daily limit. I attempted almost 10 puzzles and no message popped up until I got one puzzle wrong and it stopped giving puzzles with the usual pop-up. Was this a glitch?

But I somehow still managed to get more puzzles to do than the daily limit. I attempted almost 10 puzzles and no message popped up until I got one puzzle wrong and it stopped giving puzzles with the usual pop-up. Was this a glitch?
Your first 10 puzzles were pending puzzles and don't count towards your daily limit.
But the thing is that they scored points and ratings like normal ones. My rating increased by 200 points

But the thing is that they scored points and ratings like normal ones. My rating increased by 200 points
Yes, they still give points based on their pending rating if you get them right and give a point even if you get them wrong. It's working as expected.
You can get strings of pending puzzles and it's probably more likely when new ones get added.