STR:
Paste the following text into a new document.

        Test         		Test      
Test         		Test      
        Test         		Test      
        Test         		Test      
        Test         		Test      
		

Space to Tab (All).

Result:
The caret disappears.
If you can not reproduce it, please restart NPP and try again.

#12739 (comment).

Notepad++ v8.4.8 (64-bit)
Build time : Dec 30 2022 - 15:29:34
Path : C:---\notepad++.exe
Command Line :
Admin mode : ON
Local Conf mode : ON
Cloud Config : OFF
OS Name : Windows 10 Pro (64-bit)
OS Version : 20H2
OS Build : 19042.985
Current ANSI codepage : 1255
Plugins :
ComparePlus (1.1)
HTMLTag (1.3.6)
MenuIcons (2.0.1)
PythonScript (2)
_CustomizeToolbar (4.2)