Identified issue with Forms, Branching and answer submission

Hi there

I have a form that I have created as part of my user research for my MBA Consultancy project. Its fairly simple. No more that 25 questions, with sections and moderate branching (e.g. if yes go to Q5. if no go to Q6.)

However, in testing the form before sending it out the recipients I have found a peculiar behaviour which I can't find reference to on the forums, or answers to on a wider internet search. 

I have found that in a scenario of selecting a branch (i.e. No), and picking the an answer to the next question, and then going back to the original branch, changing my mind (i.e. from No to Yes), and picking an answer from THAT branch, it will Record the 'No' responses) regardless. I have tested different options (selecting Yes first, selecting an answer on the subsequent question, then going back and changing it to No) - and it will always record No. Is this a known feature? It will only happen if the respondant selects the answer to the subsequent question (not selecting it means it records correctly). 

Q6 - Have you undertaken training in the past 6 months?

              Yes  (branch to Q7)

              No  (branch to Q8)

Q7 - If yes, what training did you undertake?

              Multiple Choices able to be selected 

Q8 - If no, why not?

              Multiple Choices able to be selected 

a) If a respondents replies Yes to Q6, and selects options from Q7, but goes back to Q6 and then selects No, and answer Q8 - it will record the output as Q6 = No, Q8 = responses (correct - but I suspect only because of the order the responses).

b) If a respondents replies No to Q6, and selects options from Q8, but goes back to Q6 and then selects Yes, and answer Q7 - it will record the output as Q6 = No, Q7 = responses (Incorrect)

c) If a respondents replies Yes to Q6, and doesnt answer Q7, but goes back to Q6 and then selects No, and answer Q8 - it will record the output correctly as Q6 = No, Q8 = responses

d) If a respondents replies No to Q6, and doesnt answer Q8, but goes back to Q6 and then selects Yes, and answer Q7 - it will record the output correctly as Q6 = Yes, Q7 = responses         

This happens irrespective of the question (its not a unique behaviour to this question - but to any branch)

Am I missing some logic or reset needed to stop it from happening? 

Many thanks

Becky