Having multiple SPF (Sender Policy Framework) records for a domain can lead to issues and may not behave as expected. SPF records are DNS TXT records that specify which IP addresses are allowed to send emails on behalf of a domain. When multiple SPF records are published, it can create confusion and result in unpredictable email authentication outcomes.
The general rule for SPF records is that a domain should have only one SPF record. If you need to include multiple sources for sending emails (e.g., if you're using third-party email services), you should consolidate all the relevant information into a single SPF record.
Consolidate all SPF records into one single SPF record.
As below example:
Instead of adding two v=spf1 records in your DNS as below:
v=spf1 include:_spf.example.com -all
v=spf1 include:_spf.example1.com -all
Add it into single SPF TXT record:
v=spf1 include:_spf.example.com include:_spf.example1.com -all