https://www.imagemagick.org/discourse-server/viewtopic.php?f=1&p=13822

diff --git a/coders/tiff.c b/coders/tiff.c
index daab01eba1b4094c72a3b9585ad333c63b3e9d48..e0b59003cf2ee93414eeb662ad190410ec20cfcc 100644 (file)
--- a/coders/tiff.c
+++ b/coders/tiff.c
@@ -1485,8 +1485,6 @@ RestoreMSCWarning
                 }
               }
           }
-        if (image->alpha_trait == UndefinedPixelTrait)
-          image->depth=GetImageDepth(image,exception);
       }
     if (image_info->ping != MagickFalse)
       {