I don't think this is an exclusive issue to the LG G4, but I was having issues with granting certain apps access to my exFat 128gb sd card from the T-Mobile promotion. Specifically, PowerAmp did not recognize my SD card as a valid storage, for tag editing and track deleting purposes.
By default, you cannot format an SD card larger than 32gb in FAT32 format. Not even through running commands in cmd.
Anyways, the fix is to download a third-party program to format the SD card in an otherwise unsupported format. I chose to use the (free) trial version of Paragon Partition Manager. It will format your SD card to the friendlier FAT32 format. Note that formatting will delete all data on your card.
By default, you cannot format an SD card larger than 32gb in FAT32 format. Not even through running commands in cmd.
Anyways, the fix is to download a third-party program to format the SD card in an otherwise unsupported format. I chose to use the (free) trial version of Paragon Partition Manager. It will format your SD card to the friendlier FAT32 format. Note that formatting will delete all data on your card.