I formatted a USB drive using fdisk, and created three partitions. Everything seems to work fine, but Disk Utility is showing a negative amount of used space for all partitions:
Partition | Capacity | Available | Used | File system
Partition 1 | 5,12 GB | 5,46 GB | -340,8 MB | FAT32
Partition 2 | 12,29 GB | 12,63 GB | -346,2 MB | ExFAT
Partition 3 | 45,33 GB | 45,53 GB | -195,3 MB | HFS+
The drive has a MBR partition table. Switching to GUID is not an option unfortunately.
Is this normal? What can I do to fix this?
Here's a screenshot from fdisk:

Thanks in advance!
Edit: Disk Utility also shows an incorrect file count on two of the partitions (P1: 0 files, P2: 374.904 files, P3: 11.068.054 files). All partitions actually contain 0 files.