Cursor not working correctly?

[Bird up]

Hello. Started playing for the first time just last week. I noticed that whenever I jump and try to place blocks, my cursor decides to float around on its own. It only happens when I'm trying to place blocks and I'm mid jump. I thought this was some weird intended phenomenon, but after looking it up, and asking my friend if the has the same experience and he doesn't, I realise it's probably just an issue on my side. Anyone else have this issue and know why it's happening? Thanks.

BTW not using any mods, and I've tried both the in-game smart placement function and without.

 

[darthmorf]

Is it possible for you to record a video of this in action? It's tricky to determine what you mean.
Another thing - does turning smart cursor on/off help?

 

[Bird up]

I tried to get a video but I think I realise a silly oversight. I think my thumb is just sliding across my laptop's touchpad without me realizing it, and it causes the cursor to move. I often forget that thing exists lol. I'm gonna turn it off and play normally and see if it happens again.