Survival Mod Life Boat Server - Chest either dissappear or are empty in plot

LifeBoat Server : Survival Mod Sm13

Some Chest's have become invisible however you can still tap and hear them open.

Some Chests have re-appeared however contents are empty.

Double Chests have now become 2 single chests side by side.

This also happened prior to the plot reset on the 16th Jan..
I continued to use them once they became visible again, however the same problem reacurred a few weeks later when all items were lost in chests again - Then server reset so I thought maybe it had been resolved but unfortunately not.