Is there a Spotlight volume size limit?

I am asking here after finding no information on this anywhere. There doesn't appear to be any documentation on this. I am having trouble with an 18TB volume over a simple SMB network. One iMac; one Mac Mini with attached storage, ethernet 10g. I have a 6TB volume that has no issues over the same network. Settings are all the same as far as I know.

Both hard drives have a VolumeConfiguration.plist

/Volumes/Media_1/.Spotlight-V100/VolumeConfiguration.plist
/Volumes/Media_2/.Spotlight-V100/VolumeConfiguration.plist

Media_1 is the 18TB HDD Media_2 is the 6TB HDD

I ran diff on both volumes' VolumeConfiguration.plist and what jumped out was the different string in "PolicyProcess":

diff /Users/john/Documents/media_2plist.txt /Users/john/Documents/media_1plist.txt |colordiff | $(brew --prefix git)/share/git-core/contrib/diff-highlight/diff-highlight
3c3
<         16D4F012-5E09-4D3B-ACD4-6768C0DA2048 = Dict {
---
>         502C691E-AEE5-4729-B540-722F1C681B19 = Dict {
5,6c5,6
<             PolicyProcess = mdutil
<             PolicyDate = Thu Jul 25 10:07:47 CST 2024
---
>             PolicyProcess = STORE_ADD
>             PolicyDate = Tue Aug 27 19:30:08 CST 2024

Why is Spotlight choosing PolicyProcess = STORE_ADD for the 18TB HDD and PolicyProcess = mdutil for the 6TB HDD ?

What is the difference between them and can I choose which PolicyProcess Spotlight uses?

I can't find much from the network on the 18TB drive even after it has been re-indexed multiple times. Oddly it seems that while it is being indexed I get better results than once it has completed indexing.

Thanks for any insights.

Is there a Spotlight volume size limit?
 
 
Q