Zq/fix nll loss v2

[NeosZhang]

Motivation and Context

Description

Use cases (Optional)

BC-breaking (Optional)

Checklist

Before PR:

• I have read and followed the workflow indicated in the Contributors.md to create this PR.
• Pre-commit or linting tools indicated in Contributors.md are used to fix the potential lint issues.
• Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• New functionalities are covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• CLA has been signed and all committers have signed the CLA in this PR.

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ jingguo-st
❌ NeosZhang

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