@acer Hey, thanks so much for your help.  Since you seem to work for maple, I might as well clear up that it only happens to a new document.  So once I save the document, it seems to (fingers crossed) stop happening.  I am brand new to maple, and matrices are the first thing I tried, so it threw me a good curve ball.  Now that I'm experimenting a little bit with maple, it seems that sometimes saving a document, closing it, and reopening it sometimes solves similar problems like that.  

For example, I was just getting an error while trying to insert an obviously valid equation into a label.  Saving, closing, re-opening document solved it for me.  

Especially as a beginner, it can be confusing whether something is my fault or not.     

I am macos sierra mbp late 2013 + maple 2017.2

@Carl Love Thanks, good to know.  Took me a second to see it is CMD + Shft + Enter on mac, but I got it.  

..And I think that the problem is that I only encounter the problem on unsaved files.  As in, if I CMD + S (save to disk) the document, close it, and re-open it, the commands execute correctly.  Otherwise, if I open a new file or worksheet and begin typing 'A:=......' I encounter the issue.  That seems to be it, anyway.  

If anyone has a mac or knows what I'm doing wrong, perhaps they could tell me if it's a bug or a feature.  

Hopefully that solves it.  I was about to throw my computer out the window, but I luckily realized that I can't afford to replace it.  

@acer fickinfick.mw
I am not sure if saved files on Maple save history, so I will say what I did.  

Using the GUI, I made a random matrix A and B, then multiplied them together (by typing A.B )

Got: result (correct result).  

Then, I went back and physically edited B[2,1], changing it from 27, to simply 2.  I then updated A.B (by hitting return at the A.B statement), and then was left with the mess you see.  Something's happening, but I'm not really sure what.  

It was just intuitive to click on a cell in the matrix, change it, and then try to update the resulting product, but maybe I'm doing it wrong?  

Download fickinfick.mw