diff --git a/app/javascript/entrypoints/public.tsx b/app/javascript/entrypoints/public.tsx
index b2a1473dfb..f891410a3c 100644
--- a/app/javascript/entrypoints/public.tsx
+++ b/app/javascript/entrypoints/public.tsx
@@ -182,15 +182,25 @@ function loaded() {
       ({ target }) => {
         if (!(target instanceof HTMLInputElement)) return;
 
-        if (target.value && target.value.length > 0) {
+        const checkedUsername = target.value;
+        if (checkedUsername && checkedUsername.length > 0) {
           axios
-            .get('/api/v1/accounts/lookup', { params: { acct: target.value } })
+            .get('/api/v1/accounts/lookup', {
+              params: { acct: checkedUsername },
+            })
             .then(() => {
-              target.setCustomValidity(formatMessage(messages.usernameTaken));
+              // Only update the validity if the result is for the currently-typed username
+              if (checkedUsername === target.value) {
+                target.setCustomValidity(formatMessage(messages.usernameTaken));
+              }
+
               return true;
             })
             .catch(() => {
-              target.setCustomValidity('');
+              // Only update the validity if the result is for the currently-typed username
+              if (checkedUsername === target.value) {
+                target.setCustomValidity('');
+              }
             });
         } else {
           target.setCustomValidity('');