Two different FQDNs for the same IP address is forbidden, the file will be unreadable,
The /etc/hosts file will not be able to contain 2 FQDNs for the same IP address SAP Server following the standard format RFC.
# Correct format regarding FQDN :
#IP Full Qualified Domain Name Hostname
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================================= Incorrect /etc/hosts file Format =================================
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# Incorrect format regarding FQDN :
#IP 1 Full Qualified Domain Name 2 Full Qualified Domain Name Hostname
(This example is strictly forbidden you cannot have 2 FQDN for the same IP address, each IP must have only one FQDN referenced)
In case you would like to use 2 FQDN for one IP it is not standard cause one IP must be associated only with one FQDN please verify the network possibility for this request