also M.p.size and S.p.size

spec.html

@@ -35538,7 +35538,7 @@ <h1>get Map.prototype.size</h1>
           1. Let _count_ be 0.
           1. For each Record { [[Key]], [[Value]] } _p_ of _entries_, do
             1. If _p_.[[Key]] is not ~empty~, set _count_ to _count_ + 1.
-          1. Return _count_.
+          1. Return 𝔽(_count_).
         </emu-alg>
       </emu-clause>
 
@@ -35872,7 +35872,7 @@ <h1>get Set.prototype.size</h1>
           1. Let _count_ be 0.
           1. For each element _e_ of _entries_, do
             1. If _e_ is not ~empty~, set _count_ to _count_ + 1.
-          1. Return _count_.
+          1. Return 𝔽(_count_).
         </emu-alg>
       </emu-clause>