Yup. That's what I meant. It's worse though. You can't just ignore alpha channel (all the time.. Only sometimes/most of the time) due to blending.
For example a colour of 255 (red) with an alpha of 128 would cause the red to blend with whatever is behind it and also be lighter than a red with 255 alpha. Ignoring the alpha channel complete disregards this and treats a half red tone as full red. In this example. Thankfully we haven't seen such a problem yet (because Simba receives already processed images).. But yeah the black colour being treated as transparent is quite annoying at times (0 vs. 65535).