diff --git a/luamml-patches-amsmath.sty b/luamml-patches-amsmath.sty
index 68f68a8..b9556d1 100644
--- a/luamml-patches-amsmath.sty
+++ b/luamml-patches-amsmath.sty
@@ -134,12 +134,14 @@
         \strut@
         {##}
       }
-      \dim_compare:nNnF {0pt} = {
+      \dim_compare:nNnTF {0pt} = {
         \box_wd:N \c_zero_int
-      } {
+      }
+      { \place@tag@gather }
+      {
+        \place@tag@gather
         \__luamml_amsmath_set_tag:
       }
-      \place@tag@gather
       \tabskip \iftagsleft@
         \gdisplaywidth@
       \else
@@ -230,7 +232,7 @@
   \omit
   \kern -\alignsep@
   \iftag@
-    \setboxz@h { 
+    \setboxz@h {
       \@lign
       \strut@
       { \make@display@tag }