Parasitic traffic in Google Analytics (Android app)

Accidentally discovered in the statistics of the left sources, of which for 4 months already accumulated 21 pieces. In total, during this time they have tainted the picture by 88 users and 584 sessions. Carefully, by day, I unloaded everything into Excel, twirled it, looked at the data without this traffic — the indicators had changed. In particular, the conversion. From where these left users come from - it’s pretty clear, I’ve already seen these in the site’s metrics. How to clean the analytics is also understandable, because they do have common properties. Why do the “leaders” need this - there are suggestions, but with regards to websites. Do mobile apps also have a profit?



So, we meet our "heroes":


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It can be seen from the picture that none of the sources use Android, and all have zero screen views — these are the fields that can be used to configure filters in analytics. At the same time, at the beginning of the period, most sources gave “No” in the “Mobile device” field, then at the end everyone shouted “Yes”. And I, damn it, broke my head - where did my users with apples come from ... Here they are, my dears.

Could not resist, and tried to build a schedule by day. The same forum.topic57160729.darodar.com at one time was constantly hammering, albeit slightly, then it disappeared, but no, no, and it will appear again. But simple-share-buttons.com appeared at the end of March, but at once it is so powerful. It may seem that some sources have continuity, but there is too little data for such conclusions. Below is a picture of the Top 10 by the number of sessions:



Has anyone else come across this? How do you fight? Share your experience.