If a suffix were ever to produce double consonants, then it would usually be simplified to a single consonant. For the sake of example, let's say that there is no existing word for "hungry." If we use bahlok "hunger" with the suffix -kei ("hungerous"), then the resulting word would be bahlokei rather than bahlokkei.

This hasn't always been the case and older materials may show words with double consonants. There are no canon examples of double consonants occurring in regular (non-plural, non-compound) words, so this is the reason why the above guideline is in place. It helps make plural nouns like bahlokke immediately recognizable.