I hope the question is proper, I will try to explain the situation but I am not sure what kind of information might be useful.
1) A copy of cursor stays at the very top bar of Ubuntu. (where settings, wifi etc.)
2) Cursor becomes invisible when stopped.
3) When cursor stopped, there is a white box larger than cursor appearing.
I am not sure if it always occurs or not.
4) Behaviour is most clear when the cursor moves inside the terminal. It produces a random number of copy on the path it moves. Sometimes cursor itself and all the copies are moving around a bit randomly.
There is no problem with the position of the cursor. If you do not care at all about all the visuals, it clicks on the right place, and selects the correct region etc. For example, even if the cursor moves randomly around, when you click, it clicks on where it is left.
Many thanks for any suggestion, I can provide any information that could be useful.