When seq_parallel_world_size is set to a value greater than 1, should use_varlen_attn not be set to true?

I'm working on the 32k long text SFT for Qwen2 72b. When I set **seq_parallel_world_size** to greater than one and **use_varlen_attn to true**, an error occurs.
After checking, the error message is an assert error, indicating that the length of my input_ids sequence should be divisible by seq_parallel_world_size. Once I padded the sequence to the appropriate length, this error was resolved. However, after several iterations during training, the loss becomes NaN.

Here are my specific config：
`use_varlen_attn = True`
`prompt_template = PROMPT_TEMPLATE.qwen_chat
max_length = 32768
pack_to_max_length = True

# parallel
sequence_parallel_size = 4

# Scheduler & Optimizer
batch_size = 1 # per_device
accumulative_counts = 32
accumulative_counts *= sequence_parallel_size
dataloader_num_workers = 4
max_epochs = 2
optim_type = AdamW
lr = 2e-6
betas = (0.9, 0.999)
weight_decay = 0
max_norm = 1 # grad clip
warmup_ratio = 0.1`