Improve error message for no bridge found

[jsgounot]

Hi,

I run Gretel on different datasets. I've got this error message :

[FAIL] Unable to recover pairwise evidence concerning SNP #15 at position 1077 Gretel needs every SNP to appear on a read with at least one other SNP, at least once. There is no read in your data set that bridges SNP #15 with any of its neighbours.

However, when I look at my datafile with IGV, I can see multiple reads which have 2 SNPs : screenshot

Am I missing something ? Thanks !