Time Machine randomly lost avail space? Bug?

[OverSpun]

I am using a '17 15" MBP w/ 3.1ghz 16gb ram w/ high sierra.

I use a 2tb external and I have a partition for storing pictures that I took over trips and I had a partition (600gb) and it has always been enough space for Time Machine.

Today I erased the Time Machine partition and also cleared that partition and made a new with 700gb to start fresh for Time Machine but it seems that a significant amount of storage space disappeared because I had nearly free 1tb avail before I started this. Now only 494gb left in the external drive? strange.

I pressed Command+Shift+period to look for strange files that took over storage during the aforementioned process. .DocmentRevisions-V100, .Trashes, and .TemporaryItems are taking their sweet time to show me the Calculation Size but it has been 20-30mins so far.

edit: I calculated the visible folders in my picture partition total ~820gb/2000gb. It is obvious that something is off.

Thanks in advance.

 

[OverSpun]

In order to update this issue:

My backup from originally formatted from a few OSX versions back and I am not sure if that mattered at all. Anyway, I was unable to find a short and simple fix to get the lost storage ~1200gb.

I used an extra enclosure and I moved over my pictures and everything in that was in partition #1 to save them and I completely erased/reformatted/and created the two partitions that I wanted Partition #1 1300gb for pictures, etc. and Partition #2 700gb for Time Machine.

Afterwards, I ran Time Machine and it seems to be working perfect so far. Time Machine was having strange locks before and it could not complete a single backup. This may be an issue because the enclosure was not originally formatted by High Sierra?

This was the easiest way to fix it but it was not the fastest way.