diff --git a/ppl2psd.py b/ppl2psd.py
index 589671d..5a5c216 100644
--- a/ppl2psd.py
+++ b/ppl2psd.py
@@ -520,6 +520,11 @@ def build_type_layer_tysh(ly: dict, font_ps: str) -> bytes:
     editor["Text"] = String(text + "\r")
     # Txt (legacy text) value mirrors the engine text so readers agree
     td[b"Txt "].value = text + "\x00"
+    # Style/paragraph run lengths must match the new text length, otherwise
+    # Photoshop warns the text layer needs conversion / editing changes layout.
+    text_len = len(text)
+    eng["StyleRun"]["RunLengthArray"] = List([Integer(text_len)])
+    eng["ParagraphRun"]["RunLengthArray"] = List([Integer(text_len)])
 
     prof = font_profile(_font_path_for(ly))
     size_px = float(ly.get("textSize", "12") or 12) * prof["k"]