ActiveX doesn't show password input dialog for protected PDF file on Windows 10 ver. 2004

We found a problem of ActiveX below on Windows 10 ver. 2004. This problem is not occurred on Windows 10 ver. 1903. Is this bug of ActiveX?

1. Start IE11.
2. Drag and Drop "password-protected.pdf" file to the IE11 window.
3. Adobe Reader Activex in IE11 will open PDF file but password input dialog is not shown.
   *The password of "password-protected.pdf" is "abc" or "def".

We checked this issue on environment below.

• Windows 10
  • Edition: Windows 10 Pro
  • Version: 2004
  • OS Build: 19041.208
  • Windows Insider Program Slow
• Adobe Acrobat Reader DC 20.006.20042
• Adobe Acrobat Reader DC 20.009.20063
• Adobe Acrobat Reader DC 20.009.20067