Hopefully it is accepted by the other whales, even if it communicates in a different frequency. My quick research shows that blue whales can hear much higher frequencies, all the way up to about 18,000 hz, so it isn't like the other whales can't hear this one.
Hopefully the whale is accepted and communicated with, and the other whales just know them as "the one with the higher pitched voice"
I've only read the linked Wikipedia article, but is there any evidence that calling at this frequency somehow impedes communication with other whales? I don't know very much about how whales communicate and socialize.
Hopefully the whale is accepted and communicated with, and the other whales just know them as "the one with the higher pitched voice"