MacBook Dock - Duplicate Reader icons

Use a MacBook Pro with OSX Monterey version 12.7.5.  A few weeks back, not associated with any upgrade as best I can tell, a funny behavior started with Acrobat Reader.  Whenever I launch a PDF, two Reader app icons appear in the dock.  One icon has the little dot, apparently the active app.  The second does not have the dot.  I can of course drag the second icon into the trash, and it is removed from the dock.  So, all quite harmless, just annoying and curious.  Every time I open a PDF, I get the double icons.

In the Apple Support Community, others have noted this same behavior.

Any insights appreciated.