The mistake is on your side. you need engineers but you hire for people that you se as possible future friends. Your company is not acting professional. "Cultural Fit" is just another form of discriminating people you dont like — for what ever reason.
But for the candidate it has been probably the best — as companies that do hire for cultural fit n my experience also treat all of the technical staff like teenagers — no matter their age or experience. the funny thing: If you trat humans like teenagers they'll become teenagers. "Cultural Fit" is an excuse for a company not professionalise their workforce.
I personally have 20 years of experience. the minute a interview switches to cultural fit questions I will cancel it — because that company just has become a place run by self-absorbed kids in my understanding.