diff --git a/language/types/numeric-strings.xml b/language/types/numeric-strings.xml
index 2aadf65287e4..6f14313c2935 100644
--- a/language/types/numeric-strings.xml
+++ b/language/types/numeric-strings.xml
@@ -31,22 +31,33 @@ NUM_STRING       ({INT_NUM_STRING} | {FLOAT_NUM_STRING})
   any characters.
  </para>
 
- <note>
+ <warning>
   <para>
    Any string that contains the letter <literal>E</literal> (case insensitive)
    bounded by numbers will be seen as a number expressed in scientific notation.
-   This can produce unexpected results.
+   This can produce unexpected results, particularly when the significand
+   (the part of the number before the <literal>E</literal>) is <literal>0</literal>.
+   To avoid problems in comparisons, strings should usually be compared using
+   the identity operator (<literal>===</literal>) or string comparison functions
+   like <function>strcmp</function> and <function>hash_compare</function>.
    <programlisting role="php">
 <![CDATA[
 <?php
 var_dump("0D1" == "000"); // false, "0D1" is not scientific notation
 var_dump("0E1" == "000"); // true, "0E1" is 0 * (10 ^ 1), or 0
 var_dump("2E1" == "020"); // true, "2E1" is 2 * (10 ^ 1), or 20
+var_dump("0E1234" == "0E5678"); // true, because 0 * anything is 0
+/*
+    Functions that return hexidecimal strings, like hashing functions,
+    can return strings that look like scientific notation with 0 as
+    the significand.
+*/
+var_dump(md5('240610708') == md5('QNKCDZO')); // true
 ?>
 ]]>
    </programlisting>
   </para>
- </note>
+ </warning>
 
  <sect2 xml:id="language.types.numeric-string.conversion">
   <title>Strings used in numeric contexts</title>
diff --git a/language/types/type-juggling.xml b/language/types/type-juggling.xml
index df10696d4e46..75920e8a494d 100644
--- a/language/types/type-juggling.xml
+++ b/language/types/type-juggling.xml
@@ -84,6 +84,23 @@
    If the value cannot be interpreted a <classname>TypeError</classname> is thrown.
    Prior to PHP 7.4.0, an <constant>E_RECOVERABLE_ERROR</constant> was raised.
   </simpara>
+
+  <warning>
+   <simpara>
+    When using the <link linkend="language.operators.comparison">comparison
+    operator (<literal>==</literal>)</link>,
+    <link linkend="language.types.numeric-strings">numeric strings</link>
+    will be compared as numbers instead of as strings.
+    This means that <literal>"123" == "  123  "</literal> is &true;,
+    but also that <literal>"0e1234" == "0e5678"</literal> is &true;,
+    which can cause unexpected behavior when comparing hexidecimal strings
+    like those from <function>hash</function>.
+    The identity operator (<literal>===</literal>) or a string comparison
+    function, such as <function>strcmp</function> or
+    <function>hash_compare</function>, should be used to avoid unexpected
+    results.
+   </simpara>
+  </warning>
  </sect2>
 
  <sect2>