Here is a reference link to my original post. Realized that was posted in the Community section when this was originally what I probably should've posted this into:
I figured it out - turns out that Unity (probably) signs the APK's for you now. In the older versions that we were building we had to manually sign them once we had built the APK out. Hope this helps someone else out that upgraded as this was just second nature to us when we were ready to upload our APK's.
