Apple pencil trouble

When I take notes using Apple Pencil, whether ( note , notability ) the pen suddenly displays parallel lines along the screen at the same time and breaks between letters.. Knowing that the problem does not always persist, but sometimes it appears and some of them do not.. I tried to switch the tip of the pen but to no avail. I tried once before to fix it by making restart for network & really become better but the problem come back again ..

kind regards,

Omar