Add a first group to the survey (group1)
Create a question of type Array (Numbers)
In advanced settings, choose checkbox layout: no, text inputs: no, minimum value: 0, step value: 0.5, maximum value: 20.
Add some subquestions to that array (numbers) question
Add a second group to the survey (group2) and put whatever you want in there
Make sure that the survey allows next/previous navigation
Now, take the survey. In group1, choose some answers for the array subquestions. Choose some 0 answers and some nonzero answers
Click next
Click Previous. You are back on group1.
In my case, the responses I chose that were not 0 now revert back to "..." (nothing selected). The responses for which I chose 0 stay as 0.
*Summary: responses for array (numbers) do not stick when going Next and then Previous.