diff --git a/src/r_draw_flush.cpp b/src/r_draw_flush.cpp
index e729243e9..1382c3ec1 100644
--- a/src/r_draw_flush.cpp
+++ b/src/r_draw_flush.cpp
@@ -156,8 +156,8 @@ static void R_FlushQuad(void)
 
 	if constexpr (Type & ColumnFlushType::FLUSH_OPAQUE)
 	{
-		// aligned copy
-		if (((uintptr_t)dest & 7) == 0)
+		// aligned copy -- make sure our dest ptr AND viewwidth are a multiple of 8!
+		if (((uintptr_t)dest & 7) == 0 && (stride & 7) == 0)
 		{
 			const INT64 *source64 = reinterpret_cast<const INT64 *>(source);
 			INT64 *dest64 = reinterpret_cast<INT64 *>(dest);