SNP Variant Annotation

[AsoBioInfo]

I have received NGS Analysis (used the dbSNP build 134). When I chose only the new variants (no rs no. from dbSNP or 1000 Genome). After analysing the new variants, some mutations are already reported SNP in dbSNP.

I thought maybe, it is due to the old version, but when I checked the build in which the SNP was reported, it was dbSNP build 120.

What could be the possible reason of not extracting the reported SNP while using dbSNP? Can it be resolved using the newer dbSNP build?

Thanks in advance!