Was able to see his last seen only after messaging him

Whatsapp

Question guys!
My friend has his last seen set to “contacts only” well yesterday I was able to see his last seen for most of the day then it went blank around 3:00pm. I thought he deleted my number so I casually sent a message and his last seen popped up after sending the message. It said his last seen was 4:13pm and I sent the message at 4:15pm. So no way he added me again after the message, if in-fact he had deleted me. He replied at 4:50ish. I was able to see his last seen for the rest of the night.
This morning his last seen is blank again (I deleted our chat thread from yesterday.) Does this happen when someone deletes you as a contacts or when last seen is set to nobody?



System Configuration: iPhone / Safari 15.5