Why do Play Store apps show in Galaxy store? More recently I noticed something weird on my Samsung Galaxy S9 in the Galaxy Store. I have never used it for any apps other than the Samsung exclusive ones, but yet it shows me updates for some apps that are not from Samsung. For example the DJI Fly app, or the Zoom meetings app or the Discord app. App info for all theses apps say, they were downloaded from Google Play Store, but yet the Samsung Store claims it has updates for these Apps.
Is that normal? If I press update there do I suddenly get these Apps from the Galaxy store and am dependent on when they allow an update to the app?
Technically by how an app has been installed (which store, via web browser, any other app or via adb) is just a data flag once that app has been installed.
If an app is available in two stores at the same time with identical signed versions there should not be a problem even switching the stores randomly.
Problems can only arise if the app to be updated has a different versionCode (e.g. a fixed offset) in one store.
The versionCode is a number internally by Android to prevent users from downgrading an installed app. App updates can only be installed if the app signature is created by the same developer and the versionCode is greater than the installed app version.
I have seen developers that have different variants of one app (for different devices, platforms, CPU types...) where each app variant has a different versionCode.
For example the one app variant has versionCode 0x2000234 and a second variant has the versionCode 0x1000234.
Both app variants show same version string to the user but internally looking at the versionCode they are totally different.
It may now happen that if the app in the store A has the versionCode 0x2000234 and the same app of a slightly different variant has the versionCode 0x1000234 in store B.
In such a case you could install the app from store A as update of the app in store B but not the other way around.