Got IC2 1.64 up and running on my server and everything seemed to be fine until I started working on assembling a nuclear reactor. When I fill a bucket with water (to make the water and then cooling cell) the bucket fills up fine and stays full. I can empty it onto a surface with no issue. However, whenever I interact with something that has a gui overlay (a chest, crafting bench, machine, etc) or move the bucket in my inventory, the water disappears from my buckets. They are all suddenly completely empty. This does not occur in SSP, only in SMP logged into the server I am hosting on my PC.
I should note that buckets that were filled prior to my update to 1.64 work fine, until they are emptied, at which time they exhibit the same behavior.