In recent days I tried to build a guardian farm only for familiar with "how to do it".AND I used water tunnels to transport items.BUT I discovered bugs in the hoppers of ITEM SORTERS by observing for hours and hours. Sometimes filter-hopper neglects to absorb items.Sometimes filter-hopper leaks its containing items for sorting  and then they run forwards to the exit chests.It's strange and repugnant.

I had deliberately recorded the video for the bugs on the hoppers before reporting bugs.Please see video recording clips for details.