A family of Microsoft word processing software products for creating web, email, and print documents.
ProPlus = Professional Plus
however
365 is not the same as 2016 or even 2019
The first is a subscription product that is constantly being changed/tweaked. 2016 and 2019 are perpetual license products.
My 365 Home (University) was the same build as you originally posted. It has since been updated and is now version 1904 - build 11601.20204 Click-to-Run.
I just looked at the 2016 Professional Plus (HUP) and it is version 1905. I have not yet checked for this problem on that computer. I will do so tonight.
Since others are replicating your problem I think it is definitely something for MS to be dealing with. Since they are MVPs, Hans, Doug, Paul, and Stefan all have access to back-channel contacts at MS and I suspect one or more of them will raise the issue.
I again suggest that you attempt to load multiple Add-Ins and see if that makes any difference. I will be back here tonight.