Since a recent version, the default AmountsIncludeTax has turned into FALSE instead of TRUE.
This is unexpected, and also dangerous, as if you change the tax, it automatically increases the amount on the lineitem, which is incorrect for most use cases of expense claims
In batch create you need to specify all data.
It is always dangerous to leave a parameter you care about as undefined
The batch import should have a more defined interface. Skipping any validation etc is not the way to go, and exposing raw columns, which change over time should be marked as “unused column” when batch creating.