MOCA Filter

We have a four-way splitter and the MOCA filter is installed between one of the outputs, not at the input where the cable comes in. Shouldn't it be connected to the input of the splitter? I'm thinking that might be why we've been having intermittent service, especially internet. The main cable box is the only thing that's reliable most of the time. The internet goes down for 5 to 10 minutes at a time a few times a day and the slave cable box units are intermittent at times as well