This is a sirious problem!
Since Version 4.3.1 an above fputs() does not work as expectet.
Try out the example above.

Example:
<?php
$text="";
$text .= "11111"."\n";
$text .= "22222"."\n";
$text .= "33333"."\n";
$text .= "44444"."\n";
$text .= "55555"."\n";
$text .= "66666"."\n";
$text .= "77777"."\n";
$text .= "88888"."\n";
$text .= "99999"."\n";
$text .= "91111"."\n";

	$fp=fopen("./log.txt","w+");
 	fputs($fp,$text."\n");
 	fputs($fp,"\n*");
 	fclose($fp);
?>

My output looks like this:

11111
22222
33333
44444
55555
66666
77777
88888
99999
*1111

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