Well, I guess you have found the problem already: "the surveys that use custom templates".

I read this as if the surveys that use the standard templates do not have this problem?

So I would look into the custom templates and see if there is anything that causes this problem. By the way SURVEYLANGAGE should be rather SURVEYLANGUAGE, right?

Looking at the source code I can see that there are problems with the tags.Especially with

There is definitely something wrong in this template you are using.

I think you would probably need SURVEYLANGUAGE and SURVEYFORMAT.

I think the problem is that you have a typo in SURVEYLANGUAGE.

Try this and see what happens: