Can you explain this a bit? The file you show is missing the write permission changes. Having the “write” rights under Android should give you reading rights as well (confusing, I know).
Could you try adding those changes again?
If you need the file “fresh” again (but what you show looks okay, it’s just the file without changes), you can just download the bin blob and unpack it. You will find the “fresh” file under: ./vendor/qcom/proprietary/target/product/FP2/system/etc/permissions/platform.xml
The file is okay, but it’s missing the extra entry:
<permission name="android.permission.WRITE_EXTERNAL_STORAGE" >
<group gid="sdcard_r" />
<group gid="sdcard_rw" />
<group gid="media_rw" />
</permission>
Could you tell us if re-adding the changes works for you? Or have you tried that already? Don’t forget to reboot, just to be sure!