If you open a chat window and turn on any of the types of system messages, that one type will show in normal time, however after a short time other system messages will show up, this is most prominent with Enhancing because enhancing messages happen the most often, however everything shows up under the system catagory even if it's turned off.

To duplicate this bug, create a chat window, turn everything off in said chat window except one item under the system tag.  Turn on any of the items under the system tag, best to demonstrate is private item, and don't loot anything for a time, after a while everything from the [General], [Party Item], [Central Market], [Worker], [Farming], and [Enhancement] system messages will start to populate that window.  This doesn't happen with any other chat window filter other than the 7 under the system filter. 

Players like to be able to filter items in this category so they can look back in time and see what has happened 5, 10, even 300 minutes ago if that information hasn't scrolled off the chat window.

Suggestion in direct relation assuming the bug gets fixed, separate silver and trash loot from regular private and party loot, or allow us to apply filters to system messages so that whenever silver or a trash item goes in a line the entire line of text doesn't go into the chat window.