"open in Acrobat" command doesn't work for pdf attached to Outlook item

Hi. I am running Adobe Acrobat Standard with subscription, and MS Outlook for Microsoft 365 MSO (Version 2501 Build 16.0.18429.20044) 64-bit.

When I click on a pdf attached to an incoming email, the options include "open in Adobe Acrobat."  When I click on that, nothing happens—no spinning wheel, nothing. I have to click on "open," which brings up the "are you sure you want to do that?" dialog box. I click on 'yes' and the item opens in Acrobat.

Yes, it is a small annoyance, but  an annoyance nonetheless.  Anyone got any ideas to fix this? 

Thanks!