I'm running Survey123 v1.7.20 on an iPhone. If I complete a survey (provide all required responses) and then click the check mark at the bottom of the survey, I get the options "Send Later" "Send Now" and "Continue this survey" as expected. If I select "Continue this survey", make a change to one of the responses, click the check mark again, and then select "Send Now", the app sends two records instead of one. The first record has the responses as I entered them originally (before I selected "Continue this survey"). The second record has the responses as I intended to submit them (after I selected "Continue this survey"). I assume this is a bug and that "Continue this survey" should not cause the app to save the current record but should instead allow you to continue editing the current record before saving.
