Outlook Horizontal Line is not a full line and is inserted centered- office build 1912

I apologize you are seeing the issue.  We have reported this to the Outlook Team for investigation.  If the issue is pressing, you can revert to the build before the problem started.  I will post back when I know the fix is implemented for SACT Channel.  To revert to the prior build do the following:

1.  Open a Command Prompt (click into the Windows Search box and type Command Prompt to locate it)

2.  Type or paste each command line below one after the other and press Enter after each

cd %programfiles%\Common Files\Microsoft Shared\ClickToRun 

officec2rclient.exe /update user updatetoversion=16.0.11929.20606

Thank you but unfortunately that doesn't work.

I just tested those exact commands again on my test machine and they ran just fine.  In Outlook go to file, Office Account, and let me know what the details are for About Outlook like below.  

On that second line below try copy (Ctrl + C) and pasting (Ctrl + V) it into Notepad and then copy (Ctrl + C) from Notepad to paste (Ctrl + V) the Command Prompt and run it again.  Sometimes the characters don't copy well from a web site.  

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1.  Open a Command Prompt (click into the Windows Search box and type Command Prompt to locate it)

2.  Type or paste each command line below one after the other and press Enter after each

cd %programfiles%\Common Files\Microsoft Shared\ClickToRun 

officec2rclient.exe /update user updatetoversion=16.0.11929.20606

That wasn't the issue.  This is the issue:

I find this difficult to believe and even more difficult to accept.  This bug was obviously introduced into my copy of Office by a non-security update before the cessation of Windows 7 support so surely MS can't refuse to provide me with a non-security update to fix a problem that they caused on my machine in the first place, just because they no longer support the underlying OS.  Not to mention that I paid good money for my Office 2016 license and expect the product to be supported as long as they support Office 2016.  I don't recall seeing anything in the Office 2016 license that said I would no longer get support if support was withdrawn from the underlying OS.  

I have to run Windows 7 on this laptop because of other app dependencies.  On my two other laptops I'm running Office 2016 on Windows 10 (and of course the problem doesn't occur on those ones).

Please assist.

Thanks for the clarification.  This helps to understand the issue.  The screenshot does not show what Channel you are on.  I thought it was odd you would be on Semi Annual Channel Targeted.  It usually takes special steps to get on that Channel.

It appears since you are on Windows 7 you will only ever go up to Version 2002 per this article https://docs.microsoft.com/en-us/deployoffice/windows-7-support.  

If you got to File, Office Account under About Outlook does it say there anywhere what Channel you are on?  That would help to figure out a next step.  I have escalated a bug for this issue but I was reproducing it on SACT only.  If you are on Monthly Channel or Semi Annual Channel I need to ask for the fix for that channel too.  If I know what Channel you are on we can try reverting to an earlier version for that Channel.  My earlier steps were for SACT Channel only.