Micahel; I sat down with the user for some minutes and found out it were two things that got tangled up:
Firstly, services imported from Spectrum connector indeed were taking some time to show relations, probably because of the ammount of alerts it's also managing.
In the case of services coming from cmdb, what was happening is that some CIs were missing some correlatable properties in CMDB, so the connector was not importing them. Once they completed the fields in cmdb, they had to rediscover the service for the CIs to be created, but this would be completely normal due to the CIs failing to be imported the first time.
Thanks again for your help!