diff --git a/lib/mixins/acroform.js b/lib/mixins/acroform.js
index e3dd0bb0..0f9ca4fa 100644
--- a/lib/mixins/acroform.js
+++ b/lib/mixins/acroform.js
@@ -373,11 +373,13 @@ export default {
         delete options[key];
       }
     });
-    ['V', 'DV'].forEach((key) => {
-      if (typeof options[key] === 'string') {
-        options[key] = new String(options[key]);
-      }
-    });
+    if (options.FT !== 'Btn') {
+      ['V', 'DV'].forEach((key) => {
+        if (typeof options[key] === 'string') {
+          options[key] = new String(options[key]);
+        }
+      });
+    }
 
     if (options.MK && options.MK.CA) {
       options.MK.CA = new String(options.MK.CA);