I definitely noticed that I stutter more in a foreign language regardless of fluency. For example I grew up speaking 2 languages at home (English and my ancestral language) and I constantly find myself stuttering more when I speak my ancestral language. When it comes to English, my vocabulary is stronger and as a result I can find different synonyms for words that I have a tough time getting out. Whereas in my ancestral language, my vocabulary isn't as strong so I'm subjected to using the words that I know.