SD-card write permission denied when using MTP

I've just discovered that I no longer can write to my sd-card using MTP. Seems like a permission issue as I get a few permission denied errors like below in the logcat. When using MTP in TWRP recovery it works just fine.

Anyone knows how to fix this?

Quote:

04-28 14:18:51.218 5145 12786 E DatabaseUtils: java.lang.SecurityException: Permission Denial: reading com.android.providers.media.MediaProvider uri content://media/external/fs_id from pid=15493, uid=10221 requires android.permission.READ_EXTERNAL_STORAGE, or grantUriPermission()

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