My iPad ghost touches whenever I connect my keyboard

Hello, so I’ve been having this problem for quite a while now. i have a keyboard (it’s not an apple key keyboard), it was from my older sister, she used it also on her iPad and it has been causing my iPad to go crazy whenever I connect it. i thought maybe it’s on low battery but ive already charged it and its still the same, and i feel like it’s crazier now that i used it again. can someone help me why it’s behaving that way?