When sending a batch of changes to Route53 like the following which is added "." (period) on to the ends of all the Values the request returns success, but only one of the changes has been made:
{'batch': {'Changes': [{'Action': 'UPSERT',
'ResourceRecordSet': {'Name': 'cname-1.exxampled.com.',
'ResourceRecords': [{'Value': 'www-1.exxampled.com.'}],
'TTL': 3600,
'Type': 'CNAME'}},
{'Action': 'UPSERT',
'ResourceRecordSet': {'Name': 'cname-2.exxampled.com.',
'ResourceRecords': [{'Value': 'www-2.exxampled.com.'}],
'TTL': 3600,
'Type': 'CNAME'}},
{'Action': 'UPSERT',
'ResourceRecordSet': {'Name': 'cname-3.exxampled.com.',
'ResourceRecords': [{'Value': 'www-3.exxampled.com.'}],
'TTL': 3600,
'Type': 'CNAME'}},
{'Action': 'UPSERT',
'ResourceRecordSet': {'Name': 'cname-4.exxampled.com.',
'ResourceRecords': [{'Value': 'www-4.exxampled.com.'}],
'TTL': 3600,
'Type': 'CNAME'}},
{'Action': 'UPSERT',
'ResourceRecordSet': {'Name': 'cname-5.exxampled.com.',
'ResourceRecords': [{'Value': 'www-5.exxampled.com.'}],
'TTL': 3600,
'Type': 'CNAME'}}],
'Comment': 'Change: 97b8313b5b93444d977567488e5ff81e'}}
Making any other changes (that I've thought to try) works as expected so it's something specific about adding the "." on the end.
There's lots more debugging and testing in https://github.com/octodns/octodns-route53/issues/45 which was filed by a while back when an octoDNS user ran into problems. I have not been able to find a work-around for the problem. In that case each time things are synced one more record is updated and the rest of the batch is unchanged. It requires making the request N times to get all N records updated and consistent with best practices.
I've verified the behavior with manual/standalone calls to boto3.
