long time to obtain dynamic dns after reconnect

Hi. My ISP give me interenet via PPPOE. In pppoe client i set Use peer DNS, BUT when internet goes down and reconnect i cant open web pages for about 5-10 minutes(getting dns name error)
However when i set same servers in IP-DNS-Servers after internet goes down and then reconnect i can instantly open any web page. Why is that? hAP ac v6.47.8