Instead of a complex and possibly difficult to maintain regex I would approach the problem a different way. I would treat $SYSPBUFF as a file and read it line by line until I reached the "batch =" line, at which point I'd last out of the loop to cease reading any further. Lines of interest would be pushed onto an array ready for further processing. I haven't tried tidying the lines up, leading spaces, trailing comma etc., I'll leave that to the reader.

johngg@abouriou:~/perl/Monks$ perl -Mstrict -Mwarnings -E 'say q{};
my $SYSPBUFF = <<__EOD__;
 run_type = dev,
  max_monitor_time = 0.25
  verbosity_level = 2

  batch =

   (
    source = sample_document_collection_1
    files = Confucius.docx
    dest = Enterprise:Department
   )
__EOD__

open my $inFH, q{<}, \ $SYSPBUFF
   or die qq{open: < in mem data: $!\n};
my @lines;

while ( <$inFH> )
{
    last if m{batch\s*\=};
    next if m{^\s*$};
    chomp;
    push @lines, $_;
}

close $inFH or die qq{close: < in mem data: $!\n};
say for @lines;'

 run_type = dev,
  max_monitor_time = 0.25
  verbosity_level = 2
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I hope this is helpful.