Diamond Saber Sound Freeze

So my Sabers are not very old. My son and I have been enjoying them. We do light contact as he is 8 years old. However it seems like even light contact freezes the sound on my Diamond build saber. I can swing it around and everything is great till we start to play. A few hits is fine but even one can make the sound either stop entirely or freeze (playing the same note constantly). The only way to stop it is to turn my saber off and turn it back on. I made sure to get the heavy blades because I knew we would use them to play around. I don't see any damage to the hilt. I don't see any damage to the board either. I thought maybe the light shock of the blades clashing was causing it so I used a rubber band to try and keep the board in the hilt steadier and it doesn't matter. I repositioned the blade by pulling it out slightly so it isn't seated against the hilt inside and that has not helped either. Any help with this would be greatly appreciated. The other saber I purchased is not Diamond but also does not seem to have this issue. We can play with it and it does not have any issues at al. It too has a heavy blade. The only difference is the hilt and it is Emerald instead of Diamond. Just for more information my son's saber is a stunt saber and does not make noise.

Thanks in advance!