The clearlag plugin on the server that removes "ground items" is slightly broken. The clearlag gives the warnings as usual but when it clears all the entities, it does not send the message " xx entities cleared!". Not only does clear lag not display how many entities removed, it also removes minecarts. This is a problem for me and im sure it is for others. When clear lag does its sweep, minecarts, minecart hoppers etc. are removed. I have done some testing and found that if the minecart is on a rail or not it does not matter, it still is removed. Even if the hopper minecart has an ITEM inside of it the minecart will get removed and the item will get DROPPED. This will cause loss of items and break many farms on the server. Im sure this will annoy many people. I think this is a bug, could someone please look into it.
We used to have minecarts and boats not be cleared, but it looks like when we updated to 1.12 that got changed back. As for Cearlag not announcing when it clears, that indeed is a bug and we will look into fixing it. Sorry for the inconvenience!