Impala cannot read back these timestamps from Parquet, while it can read them back from textfiles.
According to the documentation, Impala should be able to handle these values somehow, as the examples contain "select cast('08:30:00' as timestamp);"
I think that this is a side effect of the fix of
IMPALA-4363, but I did not check what happens in versions that did not contain this fix.
UPDATE: I have checked the last commit before the fix of
IMPALA-4363, and it does not have this bug.