diff --git a/bip-0174.mediawiki b/bip-0174.mediawiki
index de666221e4..b60cf56c7b 100644
--- a/bip-0174.mediawiki
+++ b/bip-0174.mediawiki
@@ -69,7 +69,7 @@ Where:
 ;<tt><keylen></tt>
 : The compact size unsigned integer containing the combined length of <tt><keytype></tt> and <tt><keydata></tt>
 ;<tt><valuelen></tt>
-: The compact size unsigned integer containing the length of <tt><valuedata></tt>.
+: The compact size unsigned integer containing the length of <tt><valuedata></tt> (which must be exactly this many bytes).
 ;<tt><magic></tt>
 : Magic bytes which are ASCII for psbt <ref>'''Why use 4 bytes for psbt?''' The
 transaction format needed to start with a 5 byte header which uniquely identifies
@@ -1063,6 +1063,10 @@ The following are invalid PSBTs:
 ** Bytes in Hex: <pre>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</pre>
 ** Base64 String: <pre>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</pre>
 
+* Case: PSBT with an invalid value data due to its size being not the stated size
+** Bytes in Hex: <pre>70736274ff0100337401ff0700010000000100ff01000a73317428ff0000000001ff010301000001000000000000000076010000004100090000000000</pre>
+** Base64 String: <pre>cHNidP8BADN0Af8HAAEAAAABAP8BAApzMXQo/wAAAAAB/wEDAQAAAQAAAAAAAAAAdgEAAABBAAkAAAAAAA==</pre>
+
 The following are valid PSBTs:
 
 * Case: PSBT with one P2PKH input. Outputs are empty