Steps to reproduce:

• Open windows Notepad
• Type the following text in the notepad:

  Hello world!
  Good bye world!

• Press Ctrl+F and search for the word 'world'
• When the first occurance is found, press Escape to close the 'Find' window
• Press Ctrl+Home to turn back to the start of the document
• Press quickly the 4 following keystrokes to find the second occurrence of the word 'world' and read the line where it is located:
  • F3
  • NVDA+UpArrow
  • F3
  • NVDA+UpArrow

Actual behavior:

NVDA spells the second line.

Expected behavior:

NVDA reads the second line and does not spell it.
Here, the user does not consider having done a double key press, but having pressed 3 keystrokes quickly.

Analysis

Technically since 'F3' keystroke is not bound to a script, NVDA considers there is a double press when performing the third keystroke. Maybe a solution would be to set _lastScriptRef to None if a keystroke not bound to any script is executed.

System configuration

NVDA installed/portable/running from source:

Installed

NVDA version:

2020.2rc1

Windows version:

Windows 10 1809

Name and version of other software in use when reproducing the issue:

N/A

Other information about your system:

N/A

Other questions

Does the issue still occur after restarting your computer?

Yes

Have you tried any other versions of NVDA? If so, please report their behaviors.

Not recently.
But I remember this issue has always been there at least for one year.

If addons are disabled, is your problem still occuring?

Yes

Did you try to run the COM registry fixing tool in NVDA menu / tools?

No