Two variations of this procedure can occur.
For received duplicate prefix-SID indexes or labels for different prefixes within the same IGP instance, the router:
programs ILM/NHLFE for the first prefix-SID index or label
generates both a trap message and a syslog error message
does not program the subsequent prefix-SID index or label in the data path
For received duplicate prefix-SID indexes or labels for different prefixes across IGP instances, there are two options.
In the global SID index range mode of operation, the resulting ILM label value is the same across the IGP instances. The router:
programs ILM/NHLFE for the prefix of the winning IGP instance based on the RTM route-type preference
generates both a trap message and a syslog error message
does not program the subsequent prefix SIDs in the data path
In per-instance SID index range mode of operation, the resulting ILM label has different values across the IGP instances. The router programs ILM/NHLFE for each prefix as expected.