Video streaming issue with safari & IOS 11

Hello. Since I updated mi iPad Air wifi+3g with ios11, when streaming videos over the net, video sequences repeat themselves backward (15 seconds loop 3 or 4 times) before to keep playing the rest of the video for 5 minutes and the same issue appears again. I noticed that the timer is not accurate and acts erratically. Tried google chrome, same issue than with safari. My soon iPad Air WiFi and my wife iPad Air WiFi +3g, all os them running ios11 have the same problem. It is impossible to stream videos. Any ideas?

thanks.