Are you completely patched up in RH10? There may have been a bug that allowed leakage across DUCC
Hi there
Personally, I'm doubtful that a patch would resolve the issue. Perhaps it will, and it's certainly worth trying, but don't be too shocked if you find you need to apply the service release and nothing changes.
My own experience (as well as my gut) is whispering in my ear (or abdomen) that the most likely issue here is simple settings you configure before and during generating.
I've not seen any mention of the version of RoboHelp you are using here, so I'll use version 11 as it's most likely the most common version in use at the moment. And if you have 10 or 9 or even 2015 Release, the steps should be nearly identical.
When you look at the Single Source Layout settings, expand your Content Categories and select one. Note that for each of these, you have an ability to choose a Conditional Build Expression.
I point this out because if a conditional build expression causes items to not be included in the output, the items also should not appear in the search.
My thought here is that you need to carefully configure some Conditional Build Tags, then associate the tags with the topics that do not apply for each category. So, for English topics, create and associate a tag named "English". Same for other languages. Then when you prepare to generate, examine each category, click that Define button and exclude the languages that don't apply. So if you have four languages, perhaps English, Spanish, French and German, and your category is for English, you would create a Build Expression that looks like this:
Give that a go and see how you fare.
Cheers... Rick 
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