GPU/HW: Flipping the mask bit test should flush

src/core/gpu_hw.cpp

@@ -3684,6 +3684,7 @@ void GPU_HW::PrepareDraw(const GPUBackendDrawCommand* cmd)
     if (texture_mode != m_batch.texture_mode || transparency_mode != m_batch.transparency_mode ||
         (transparency_mode == GPUTransparencyMode::BackgroundMinusForeground && !m_allow_shader_blend) ||
         dithering_enable != m_batch.dithering || m_texture_window_bits != cmd->window ||
+        m_batch.check_mask_before_draw != cmd->check_mask_before_draw ||
         m_batch.set_mask_while_drawing != cmd->set_mask_while_drawing ||
         (texture_mode == BatchTextureMode::PageTexture && m_texture_cache_key != texture_cache_key))
     {