In the “tag variants” section of variant summary pages in Open Targets Genetics, why do some SNPs have a posterior probability and others don’t?

Only variants that are in a 95% credible set (and have an absolute probability > 0.1%) have their posterior probability shown in this table.

Tag variants for 1_55055436_G_A (rs693668) (Open Targets Genetics) showing a posterior probability for only one of the SNPs.

For more information on credible sets see: In Open Targets Genetics, what is the “credible set overlap”?