This sounds like a network issue. How are you connected to the network?
if you run a long (10 - 20 minutes) iperf3 test are there also such periods of freeze?
Sometimes it is important to check the network performance between your OSMC Device and the device providing your media (NAS, Server, PC). Especially when you are connected via wireless the throughput variations can harm you viewing experience.
This short How To should give you the required information how to install iperf3 and how to run the respective tests. When doing these tests it is suggested to have a simple setup (single switch between Sender and Receiver and avoid other traffic on the …