I was investigating a bit and, no is not fixed :)

I avoid file type association and I always do: perl myprog.pl in the command prompt. I associate .pl and .pm files with my text editor Notepad++

I have followed your steps and then in an unpriviledged cmd prompt: 

C>ftype tempPerl
tempPerl="C:\EX_D\ulisseDUE\perl5.32.64bit\perl\bin\perl.exe"

>assoc .pl
.pl=tempPerl

>c:\Users\Tizio.Caio\Desktop\hello.pl

[download]

Notepad++ was launched without any effect of the file type association.

The registry show what is was set previously and explain the actual behaviour:

C>REG QUERY HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Fi
+leExts\.pl

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\F
+ileExts\.pl\OpenWithList
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\F
+ileExts\.pl\OpenWithProgids
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\F
+ileExts\.pl\UserChoice

C>REG QUERY HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Fi
+leExts\.pl\OpenWithList

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\F
+ileExts\.pl\OpenWithList
    a    REG_SZ    {1AC14E77-02E7-4E5D-B744-2EB1AE5198B7}\OpenWith.exe
    MRUList    REG_SZ    ba
    b    REG_SZ    notepad++.exe


C>REG QUERY HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Fi
+leExts\.pl\OpenWithProgids

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\F
+ileExts\.pl\OpenWithProgids
    pl_auto_file    REG_NONE


C>REG QUERY HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Fi
+leExts\.pl\UserChoice

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\F
+ileExts\.pl\UserChoice
    ProgId    REG_SZ    Applications\notepad++.exe
    Hash    REG_SZ    TXlP+tcVMI0=

[download]

Then I googled and I found:

The above tests executed on: Microsoft Windows 10 Pro 0.0.19041 N/D build 19041

L*

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

In reply to Re^2: File association on Windows -- broken? by Discipulus
in thread [FIXED] File association on Windows by stevieb

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