ASR1002-X issue after upgrading

I have 4 ASR 1002-x acting as PPPOE server 

i upgrade three of them to asr1002x-universalk9.16.09.07.SPA.bin and Rommon to 16.7(1r) as recommended in 

https://www.cisco.com/c/en/us/td/docs/routers/asr1000/rommon/asr1000-rommon-upg-guide.html#con_60840

but since the upgrade our PPPOE users start suffer from sudden stop in some websites and apps for 1 minutes or more and at random times then everything return to normal 

this issue keep happing along the day , this issue keep happening along the day , the sites are reachable through ping and DNS resolve its domain normally,  the issue happen only on two of this three routers 

if you have any clarify i will be appreciate