Adobe Acrobat Rearer Uising CPU when Minimized

I am running Adobe Actobar Reader DC  Continuus Release | Version 2021.007.20099 64-bit in Windows 10 21H1 64-bit.  There are times when the application, when minimized, uses lots of CPU.  I ran ProcessExplorer and got screen-shots of the Threads and Performance Graph tabs.  I also used ProcessMonitor to get a trace.  The PID that was using CPU was 7144.  In the ProcMon trace there are 3,185 trace records: 3058 ReadFile and 127 CreateFile.  The process is reading these files:

      57 Acrobat.dll

        7 Acrobat.exe

        4 JP2KLib.dll

  3001 Downloads\PDF file I had downloaded and opened

I have no idea why Acrobat Reader would be reading the PDF file that many times when the Reader process has been minimized.  The trace ran from 9:10:44 until 9:13:43.  PID 7144 was usng 6% of the CPU.  I had to Exit the process and restart it.  My current two Reader PIDs have two open files and are using 0% CPU.  ProcessExplorer showed that the CPU of PID 7144 was being consumed at Acrobat.exe+0x2310.  What is happening?  Thanks.