ContentTranslation is limited in handling templates. It can adapt some templates that appear in the source article, and it skips many others.

There is no way to insert a new template that doesn't appear in the source article at all while editing the translation. They can be inserted after the creation, of course, but some templates are unique to a language and very common in it as a usual editing practice that it would be comfortable to insert them while translating.

One example is Template:כ in Hebrew, which inserts an RLM. The custom in the Hebrew Wikipedia is to use the template rather than the explicit control character, and many translators try typing {{כ}} while editing, which results in <nowiki>{{כ}}</nowiki>.