Ps4 connects itself with wlan again?

I wanted to take my ps4 to colleagues with Problem is I do not know my wlan password itself and when I'm with colleagues I wanted to use his Wi-Fi and then the day after tomorrow my wlan stores the Wi-Fi wlan as the mobile phone and you have to re-enter nothing?

For me it is honestly times like that, but mostly it saves the WLAN and connects automatically but I had moments where an error appeared and I had to enter the password again, but it was very rare with me.