ng-repeat-start should not return extra null element

if use findRepeaterRows to find web elements inside ng-repeat-start and ng-repeat-end,  an additional null element will be returned. sample webdriver response result like

{"sessionId":"ceaa220df6d1aea288c80924820c066b","status":0,"value":[null,{"ELEMENT":"0.2879988788627088-17"},{"ELEMENT":"0.2879988788627088-18"},{"ELEMENT":"0.2879988788627088-19"},{"ELEMENT":"0.2879988788627088-20"}]}

the 1st element in the result is null