My phone is downloading "Google Play", over mobile data

My phone randomly shows the Download Manager downloading "Google play". I usually cancel this download since it seems fishy to me, and that's what my question (asked below) is about. Since this sounds all too common and like many questions posted here, let me clarify what this is not: - This is not a download within the Google Play store. - All apps are up to date in my play store. - My OS was recently updated to Oreo (Samsung Galaxy S8). - All my Samsung apps are also up to date. - As far as I can tell, I have set all updates to happen only on wifi, not on mobile data connections. - The download is happening via Download Manager. Long-press etc shows me info about the default "download manager" app itself, not about what it is trying to download. This reeks of malware to me, wherein some shady app might have just named itself "Google Play" so that I allow it to be downloaded and run it. A malware scan shows nothing (of course, I aborted the attempted download so that file was not scanned, but there seems to be no trojan trying to download more stuff) My questions are: - Has anyone seen this issue? Is it a regular deal, so that I should just let the phone do what it wants? - If this is "business as usual", how do I set it to happen on wifi and not on mobile data? - If this seems suspicious, what steps could I take to further investigate / remove the problem?