Incorrect Capacity for Time Machine on my RN2120 v2

I can't seem to find a solution anywhere, at least no posts with working links. The unit has about 8TB usable storage. I had 5GB reserved for a private Time Machine, which was nearly filled up, along with 3 for the shared Time Machine. About 5TB were used for the Time Machine and other items. Now, if I navigate to Time Machine settings, it says only 3TB are available, so the 5TB is showing up as used data, when it's supposed to be the Time Machine. I tried updating FW, rebooting, but the software won't recognize that Time Machine data as being Time Machine data, so it'll only let me use the remaining 3. Time Machine on the iMac shows that 0 of 3TB are available for backups, but before this, it said 500GB of 5TB were available. It's annoying me and I really don't want to disable/enable Time Machine to wipe my existing sparbundle file since I will likely need to access the old time machine backups in the future. Any ideas anyone? I appreciate it!