Printer sounds like it's hitting the print

Printing a relatively large model on my printer, and it occasionally sounds like it’s hitting the top of the print while it’s moving about. Any idea what can be causing this? Is it a common experience?

https://www.reddit.com/r/3Dprinting/comments/1cono82/sovol_sv06_plus_hitting_supports/

Hi,
Either the leveling was not done correctly, or your platform is bulging.
I advise you to redo the leveling and run a bed visualizer?
Good evening

for this is the z-hop feature. maybe the retrac is to short or the k-factor aka pressure advance is not set right. the print stops pushing the filament but it dripes out and without z-hop you can probably hit on it after that.
also can this happend, if your belttension goes lose.