Well if you've seen my previous questions, you should expect something obscure and weird and I'm happy to provide another instance in Billy's Wacky House of IT Wonders. I finally solved this issue and wanted to share it.
So on my main PC, using my domain admin credentials, I am no longer able to access 2 out of 3 network shares (3rd share I created) or the administrative share on our backup server. However, I can access those shares when logged into a different computer. Also when logged into my main PC with a Test Domain Admin account, I can access the shares.
So the problem seems to be limited to my user account on my PC only. I have recreated my profile with no dice. I verified nothing was mapped via "net use". Even mapping and deleting JIC.
So it being limited to 1 account on 1 machine really narrowed down the problem. I checked the Credential Manager in Win10 and apparently it decided to save the connection information for the 1 share I created (restricted permissions utilizing a specific account for our Voicemail automated backups). Once I deleted the 2 entries in Credential Manager, I was able to access the share.
Hope this helps someone. I'm still not sure how/why Windows 10 decided to save those credentials like that for the machine itself instead of the network share specifically, but its all fixed now!