diff --git a/src/core/models/TextFormatModel.php b/src/core/models/TextFormatModel.php
index 1be51a155d5077bb471a3b766f3b246dd18bd6f6..f61d4da53277f4013ea28192d6b727d1db2cd85c 100755
--- a/src/core/models/TextFormatModel.php
+++ b/src/core/models/TextFormatModel.php
@@ -131,7 +131,7 @@ class TextFormatModel
     public static function camelToSnake($subject) {
         $snakeCaseSubject = '';
         foreach (str_split($subject) as $index => $character) {
-            if ($index > 0 && strtoupper($character) == $character && strpos('0123456789', $character) === false) {
+            if ($index > 0 && strtoupper($character) == $character && strpos('0123456789_', $character) === false) {
                 $character = strtolower($character);
                 $character = '_' . $character;
             }