Insider Updates

I have multiple Microsoft accounts (and PCs, and licenses). One of the accounts (the one I'm posting from) has Office 365 and was in the Office Insider program, though this particular computer is not registered as one of my 365 systems, and what I installed on it is Office Home and Student 2016. Also, I've recently opted out of Office Insider. This computer needs to stay on Office 2016 Home and Student for compatibility, as I use it to teach a group/computer lab where all computers are on Office 2016 Home and Student. The image below shows the product information for this/the lab's computers. My question is this:

While the activated product does in fact show Office Home and Student 2016, the "about PowerPoint" shows Version 1912 (Build 12325.20288 Click-to-Run), which I believe is one of the latest Insider builds. I've noticed some incompatibilities between my and the other lab computers - am I on Office Home and Student 2016 or somehow still on Office 365/Insider)? And if this computer is on Office Home and Student 2016, how do I determine what Version/build it's on?

Version 1912