Yeah, if it is a carbon filter, this is expected. What you are actually seeing is carbon fines suspended in the liquid. When they put the carbon into the filter and it jiggles around in transit to wherever it goes until it reaches you, little pieces of the carbon break loose. These pieces are smaller than the porosity of the filter holding in the rest of the carbon and will wash out when water is poured through. It isn’t really harmful, but is unsightly and might end up catching on your teeth like coffee grounds might. It’s best to pour a few volumes through the filter to wash out the fines to eliminate this issue.