Writing bug with the mobile version of WoP and WoT

I use a cellular phone with android and I have big problems when I have to write topics, owls and also grade classes. When I write, every few words or even letters, the part of the screen where the text goes turns blanck and then in a second returns. That is very annoying because I can't write fast and sometimes it's worse.

I tried to use chrome or the normal google application for internet, but nothing changed.

Am I the only one with this problem? I never had a problem like this before.