I'm not sure if the IVE was simply generated incorrectly, or if the Image::getTotalSizeInBytesIncludingMipmaps() was modified since the file was generated. Either way, I added a simple check in the IVE loader so that it clears the mipmap offsets if the actual data size does not match the computed data size. This seems like a safe fallback since the mipmap data can be automatically generated, and it fixes the problem in my case.
Also, while looking into this issue, I noticed that the osgDB::InputStream class applies the serialized image allocation mode. However, since the serializer is allocating the image data itself, it seems like it should force the allocation mode to USE_NEW_DELETE.
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