Double quotes in delimited formats help deal with whitespaces and usage of special characters.
Consider the following experiment with Excel:
Enter into A1 the following value: [space]Test"Value[space] and then save it as a tab-delimited text file. You will get the shown value.
Note the duplication of quotes when inside the quotes (1 character became 2). So an accidentally typed quote (we know it is accidental in the screenshot because there was another Tienda rodas above this one without these quotes) became two.
Survey Solutions trims the content of text questions removing the leading and trailing spaces, so you don’t see the quotes used this way very often, but based on your screenshot the quotes appear in the value of a variable (which is just space in this case).
Perhaps you are using it for displaying some generated text as a substitution? In that case do you really need it in your output? Probably not, and having the value to .…_CombustibleCocinar is sufficient?
I wouldn’t place any critical functionality on this. We might very well decide to trim the values of variables too one day. Instead look at the definition and come up with a visible marker for that situation instead of a whitespace. For example: “other”, or “not defined”, or “unknown”, etc.