diff --git a/RenderSystems/GL3Plus/src/OgreGL3PlusTextureGpu.cpp b/RenderSystems/GL3Plus/src/OgreGL3PlusTextureGpu.cpp
index 1824125f6c9..f1712e5c843 100644
--- a/RenderSystems/GL3Plus/src/OgreGL3PlusTextureGpu.cpp
+++ b/RenderSystems/GL3Plus/src/OgreGL3PlusTextureGpu.cpp
@@ -859,7 +859,8 @@ namespace Ogre
     //-----------------------------------------------------------------------------------
     void GL3PlusTextureGpuRenderTarget::setOrientationMode( OrientationMode orientationMode )
     {
-        OGRE_ASSERT_LOW( mResidencyStatus == GpuResidency::OnStorage || isRenderWindowSpecific() );
+        OGRE_ASSERT_LOW( mResidencyStatus == GpuResidency::OnStorage || isRenderWindowSpecific() ||
+                         isRenderToTexture() && mWidth == mHeight );
 #if OGRE_NO_VIEWPORT_ORIENTATIONMODE == 0
         mOrientationMode = orientationMode;
 #endif
diff --git a/RenderSystems/Vulkan/src/OgreVulkanTextureGpu.cpp b/RenderSystems/Vulkan/src/OgreVulkanTextureGpu.cpp
index 8d3bb1d2699..6a30fba7284 100644
--- a/RenderSystems/Vulkan/src/OgreVulkanTextureGpu.cpp
+++ b/RenderSystems/Vulkan/src/OgreVulkanTextureGpu.cpp
@@ -1014,7 +1014,8 @@ namespace Ogre
     //-----------------------------------------------------------------------------------
     void VulkanTextureGpuRenderTarget::setOrientationMode( OrientationMode orientationMode )
     {
-        OGRE_ASSERT_LOW( mResidencyStatus == GpuResidency::OnStorage || isRenderWindowSpecific() );
+        OGRE_ASSERT_LOW( mResidencyStatus == GpuResidency::OnStorage || isRenderWindowSpecific() ||
+                         isRenderToTexture() && mWidth == mHeight );
 #if OGRE_NO_VIEWPORT_ORIENTATIONMODE == 0
         mOrientationMode = orientationMode;
 #endif