This happens quite often sadly - for example I fixed 8 bugs in Gemma https://x.com/danielhanchen/status/1765446273661075609, multiple bugs in Llama, Mistral, Qwen, a gradient accumulation bug https://x.com/danielhanchen/status/1846235913443262891 etc
I wouldn't blame model training teams - sadly it's relatively hard to coordinate large teams so it might have been overlooked.
But hey - I'm always here to fix them up :))