diff --git a/spec/plaindate.html b/spec/plaindate.html
index 0f8057ffc..ca8f30a79 100644
--- a/spec/plaindate.html
+++ b/spec/plaindate.html
@@ -730,6 +730,9 @@ <h1>
           1. If _sign_ × (_d1_ - _isoDate2_.[[Day]]) > 0, return *true*.
         1. Return *false*.
       </emu-alg>
+      <emu-note>
+        <p>This operation intentionally uses overflow ~constrain~ when regulating the year-month. As a result, adding the duration returned by `.since` or `.until` to _baseDate_ may cause a *RangeError* exception when _overflow_ is ~reject~.</p>
+      </emu-note>
     </emu-clause>
 
     <emu-clause id="sec-temporal-regulateisodate" type="abstract operation">