cursor with different batch-size will return different result

[Himan000]

Example as https://python-driver-for-arangodb.readthedocs.io/en/master/cursor.html.
There are 5 docs in collection. If iterate cursor with below code:
cursor = db.aql.execute(
'FOR doc IN students FILTER doc.age > @Val RETURN doc',
bind_vars={'val': 17},
batch_size=2,
count=True
)
while cursor.has_more():
item = cursor.next()
print(item)
There result will be correct:
_{'_key': 'Abby', 'age': 22, '_id': 'students/Abby', '_rev': 'Y-w78wW--'}
{'_key': 'John', 'age': 18, '_id': 'students/John', '_rev': '_Y-w78wW--B'}
{'_key': 'Mary', 'age': 21, '_id': 'students/Mary', '_rev': 'Y-w78wa--'}
{'_key': 'Suzy', 'age': 23, '_id': 'students/Suzy', '_rev': '_Y-ysmze--F'}
{'_key': 'Dave', 'age': 20, '_id': 'students/Dave', '_rev': 'Y-ysmze--H'}
But if change from batch_size=2 to batch_size=3, only 4 docs return.
_{'_rev': 'Y-w78wW--', '_key': 'Abby', 'age': 22, '_id': 'students/Abby'}
{'_rev': '_Y-w78wW--B', '_key': 'John', 'age': 18, '_id': 'students/John'}
{'_rev': 'Y-w78wa--', '_key': 'Mary', 'age': 21, '_id': 'students/Mary'}
{'_rev': '_Y-ysmze--F', '_key': 'Suzy', 'age': 23, 'id': 'students/Suzy'}
Could any anyone help this case or is it a bug?

[Himan000]

I think I find the sovlution by replacing looping to below code:
for doc in cursor:
print(doc)