There is one very distinctive L21 haplotype cluster that at present appears to be entirely Ashkenazi Jewish, with the marker values 388=11, 392=14, 459b=9, and 464c=15. But thus far it has not been found in Ireland or anywhere even close to Ireland (it is Eastern European), and has no known connection to the "Cohen Modal Haplotype" or the levitical priesthood.
You are probably getting Irish haplotype neighbors not because your y-dna is Jewish but because it is Irish.
At a GD of 3, I show a strong match to Western Russia on an Indigenous population analysis:
Matches at a Genetic Distance of 3:
Population Set # Matches Population Size Match %
Tambovskaja, Western Russia 19 47 40.43%
Orlovskaja, Western Russia 14 41 34.15%
Tverskaja, Western Russia 12 43 27.91%
Central Poland 70 255 27.45%
Central Poland 70 255 27.45%
Penzenskaja, Western Russia 20 80 25.00%
Smolenskaja, Western Russia 10 42 23.81%
Iwanovskaja, Western Russia 9 39 23.08%
Lithuanian, Northeastern Poland 28 124 22.58%
Ibiza (Balearic Islands) 21 96 21.88%
Podlasie, Northeastern Poland 37 181 20.44%
Mansi from Northwest Siberia 5 25 20.00%
Ryazanskaja, Western Russia 7 35 20.00%
I thought this strange for an L21.