diff --git a/src/editor/parts.ts b/src/editor/parts.ts
index ed48fcbe4e..f707d8374e 100644
--- a/src/editor/parts.ts
+++ b/src/editor/parts.ts
@@ -186,7 +186,11 @@ abstract class PlainBasePart extends BasePart {
         }
         // when not pasting or dropping text, reject characters that should start a pill candidate
         if (inputType !== "insertFromPaste" && inputType !== "insertFromDrop") {
-            return chr !== "@" && chr !== "#" && chr !== ":";
+            if (chr !== "@" && chr !== "#" && chr !== ":") {
+                return true;
+            }
+            // only split if the previous character is a space
+            return this._text[offset - 1] !== " ";
         }
         return true;
     }