extract_instruments

[Hejiewang]

when I used this code to extract data, a error always happens. my code is HT_data<-extract_instruments(outcomes="ebi-a-GCST90018855",clump=FALSE,p1=5e-08)
In .fun(piece, ...) :
Duplicated SNPs present in exposure data for phenotype 'Hashimoto thyroiditis || id:ebi-a-GCST90018855. Just keeping the first instance
But when I used clump=TRUE, this code correctly runs. I want to know why.