update

here several methods to clarify what your file contains.

I prefer Data::Dump but you might not have it installed.

use strict;
use warnings;
use Data::Dump qw/dd/;
use Data::Dumper;

while (<DATA>) {
    chomp;
    print "<$_>\n" if /\.$/;
    dd $_;
    warn Dumper $_;
}


__DATA__
Inventories

Trade receivables

Assets

This item includes impairment losses.
[download]

with chomp

$VAR1 = 'Inventories';
$VAR1 = '';
$VAR1 = 'Trade receivables';
$VAR1 = '';
$VAR1 = 'Assets';
$VAR1 = '';
$VAR1 = 'This item includes impairment losses.';
"Inventories"
""
"Trade receivables"
""
"Assets"
""
<This item includes impairment losses.>
"This item includes impairment losses."
[download]

without chomp

$VAR1 = 'Inventories
';
$VAR1 = '
';
$VAR1 = 'Trade receivables
';
$VAR1 = '
';
$VAR1 = 'Assets
';
$VAR1 = '
';
$VAR1 = 'This item includes impairment losses.
';
"Inventories\n"
"\n"
"Trade receivables\n"
"\n"
"Assets\n"
"\n"
<This item includes impairment losses.
>
"This item includes impairment losses.\n"
[download]

• What do you mean "not recognized", are they are printed?
• What happens if you run my code?
• What happens if you copy my DATA lines into a file?

My guess is that your input is different to what you think.

Do you probably have weird line endings?

use strict;
use warnings;
my $file = \do{my $disk_file =
     "Inventorier\n"
    ."Trade receivables\n" 
    ."Assets\n"
    ."This item includes impairment losses.\n"
    ;
};


open (IN,'<:encoding(UTF-8)', $file) or die "Could not open '$file'$!"
+;
*OUT = *stdout;


    while (my $text = <IN>) {

    #$text =~ s/^[a-z].*[a-z]$//gmi;
    $text =~ s/^[a-z].*[a-z]\n$//i;

      print OUT $text;

    }

  close (IN) or die "Could not close input file: '$file' $!";
[download]

Note that I have not made any other changes to your posted code (except to remove the looping and the output files.) Even though this should 'work', I prefer LanX's first suggestion.