Not all references gathered

Hi, thank you all for your great work with BackstopJS, first of all.
I am using v3.0.38 with npm v5.6.0 and nodejs v8.9.4. I am using the global version of backstopJS, not a version installed locally inside my project.
It is all working except for a little boring detail.
When BackstopJS is gathering references (with backstop reference command) it is skipping first element in viewport's array, so it's creating correctly only references for viewport element with index 1, 2, 3 but not with index 0. Moreover, if I try and add twice first element, second one is correctly gathered, so it seems it is really skipping first element inside the array.



I searched other posts for similar issues but could not find any. Is there some fix or workaround?