Eval bug: DeepSeek-V4 emits only repeated `<` whenever a prompt spans more than one forward pass — CUDA flash attention (clean on CPU, clean

当 DeepSeek-V4 模型的 prompt 需要多个 forward pass(即一个 batch/ubatch 装不下)时,在 CUDA + flash attention 开启的情况下,模型只会输出重复的 `<` 字符。优先排查是否启用了 CUDA flash attention,并尝试用








