TMemIniFile.Create hanging when called in ServiceStart

Question

In a service running under system account the code below hangs in the TMemIniFile.Create without errors. If we replace it with TIniFile, it works fine.
It's a Delphi Tokyo 10.2.3 Win32 app running under Windows Server 2012R2. There's no concurrent access to the INI file.
This is the first time (first client) we see this, it has been running fine on many machines.

I have no idea what to look for further. Any ideas?
It 'works' now because we switched to TIniFile, but I'd like to find the cause. From other posts I read here, TINIfile seems to be more finicky than TMemINIfile, my situation is the reverse.
There are no special characters in the INI file and it is created with an ASCII editor.

// This is set in the ServiceCreate:
FIniFileNaam := ChangeFileExt(ParamStr(0),'.INI'); 

// This is called from the ServiceStart:

procedure TTimetellServiceBase.LeesINI;
var lIniFile : TMemIniFile;
begin
   LogMessage(FIniFileNaam, EVENTLOG_INFORMATION_TYPE, cCatInfo, cReadINI);  // Logs to event log, we see this
   FStartDir := ExtractFilePath(ParamStr(0));

   if assigned(FLaunchThreadLijst) then FreeAndNil(FLaunchThreadLijst);
   FLaunchThreadLijst := TStringList.Create;
   try
      if FileExists(FIniFileNaam) then
      begin
         // Lees waarden uit INI file
         lIniFile := TMemIniFile.Create(FIniFileNaam);  // This is the call that hangs. The service is unresponsive now.
         try
            FLaunchThreadLijst.CommaText := lIniFile.ReadString(INISECTIE_SERVICETASKS,'RunIniFiles','');
            FMaxTaskDuration := lIniFile.ReadInteger(INISECTIE_SERVICETASKS,'MaxTaskDuration',FMaxTaskDuration);
         finally
            FreeAndNil(lIniFile);
         end;
      end;

   finally
      if (FLaunchThreadLijst.Count = 0) and FileExists(FStartDir + FExeName) then
         FLaunchThreadLijst.Add(SDEFAULTTHREADNAME);
      LogMessage(Format('FLaunchThreadLijst.CommaText: %s (%d items)',[FLaunchThreadLijst.CommaText,FLaunchThreadLijst.Count]), EVENTLOG_INFORMATION_TYPE, cCatInfo, cLaunchList);
   end;
end;

FWIW, INI file contents:

[TASKMANAGER]
RunIniFiles=TTTasks.ini
MaxTaskDuration=2
RestartIniFiles=
KillIniFiles=