Hey there, @Wap!
Is this a Desktop PC or a laptop? If it's a PC, you should definitely try reseating the connections and the whole drive itself, making sure there are no loose screws. Vibrations could cause unusual noises when the drive is under load. However, these noises could also be indicating internal hardware failure!
So I'd recommend you back up all important files from this SSHD somewhere else immediately to avoid any potential data loss.
You should also try plugging it to another computer, if you have access to one and see how the SSHD behaves in there as well. I'd also suggest you run a diagnostic test on the drive using its brand-specific utility. However, keep in mind that some hardware malfunctions cannot be detected by a software. Since the hybrid drive is relatively new, you should also consider sending an RMA request to the reseller or the manufacturer's customer support.
Good luck! Hope this helps you.
SuperSoph_WD