fix(batch): warn when fragment mapping not found

[zwang28]

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What's changed and what's your intention?

Batch should not panic even metadata is inconsistent somehow.

#19091

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[BugenZhao]

I think this is somehow an assertion. May I ask whether we know the reason why it can be inconsistent?

[kwannoel]

I think this is somehow an assertion. May I ask whether we know the reason why it can be inconsistent?

I think @zwang28 is still investigating. @zwang28 could you open an issue to track it with more details? Thanks

[zwang28]

I think this is somehow an assertion. May I ask whether we know the reason why it can be inconsistent?

I think @zwang28 is still investigating. @zwang28 could you open an issue to track it with more details? Thanks

#19091