Tamagotchi P's fourth puzzle piece

Hi I'm new here and my Tamagotchi P's is my first Tamagotchi since the 90's! ^_^ I have looked everywhere online, here and Tamazone but I can't find the answer to my question. I hope it's okay that I am asking it here. I have had two generations on my Tamagotchi P's, but I can't get the fourth puzzle piece. I wait 48 hours like everyone says to, but I still don't get it. So I guess my question is do they just wake up with it one day? Will it only happen at a certain time of day? Is there a reason I am not getting it? I have had my current adult since Sunday morning. Do I just need to keep waiting? I married my last adult off accidentally after a date in the park. Oops. But I would really like to get all four of the puzzle pieces from now on.

Thank you!

If this is against any rules please forgive me, I tried to make sure it was okay first.

How long have you waited?

He changed into an adult on Sunday morning, so since then. It says he is 4 years old if that has any impact on it?

Wait until later in the day. If he's 4 years old, that means it's the day he will get his Happy Symbol, but you just need to wait until the right hour (exactly 48 hours after he evolved)