I removed this permission from my app even removed plugin which used it but still got this rejection. I checked all android manifest files, even all logs there is no REQUEST_INSTALL_PACKAGES permission
Solution 1: Cương Nguyễn
It may be in some library that you are using, which cannot be controlled, so remove it by add this to your
<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" tools:node="remove"/>
Solution 2: Kamlendra Pandey
I had the same issue. Actually, there will be some other older build which is containing REQUEST_INSTALL_PACKAGES permission in the Testing(OPEN, CLOSED, INTERNAL) section that's why they are rejecting the app.
You can find such a build in the Policy Status section of the app console. Btw, To fix this you have to suspend all such kinds of builds.
One way of doing it is, Take a fresh build and upload it to Internal Testing then promote this build to OPEN testing & after then promote it to production from the OPEN testing section. This way it will exclude the older build and your fresh build will be approved. Added Screenshot for reference.