diff --git a/common/src/app/common/data.cljc b/common/src/app/common/data.cljc
index 86a733ee28..e9bb3a918f 100644
--- a/common/src/app/common/data.cljc
+++ b/common/src/app/common/data.cljc
@@ -782,7 +782,8 @@
                 (not (js/isNaN v))
                 (not (js/isNaN (parse-double v))))
 
-     :clj  (not= (parse-double v :nan) :nan)))
+     :clj  (and (string? v)
+                (not= (parse-double v :nan) :nan))))
 
 (defn read-string
   [v]
diff --git a/common/test/common_tests/data_test.cljc b/common/test/common_tests/data_test.cljc
index d85e835af9..3228ec0298 100644
--- a/common/test/common_tests/data_test.cljc
+++ b/common/test/common_tests/data_test.cljc
@@ -841,6 +841,9 @@
   (t/is (d/num-string? "-7"))
   (t/is (not (d/num-string? "hello")))
   (t/is (not (d/num-string? nil)))
+  ;; non-string types always return false
+  (t/is (not (d/num-string? 42)))
+  (t/is (not (d/num-string? :keyword)))
   ;; In CLJS, js/isNaN("") → false (empty string coerces to 0), so "" is numeric
   #?(:clj (t/is (not (d/num-string? ""))))
   #?(:cljs (t/is (d/num-string? ""))))