I do that for my own native language - Portuguese - because some words I only learned or mostly used when I was living abroad or from sources in other languages so the word that pops in my mind isn’t in Portuguese (generally its in English but sometimes in other languages).

This is especially so for technical words and often used words which are close in both languages but not exactly the same.

So this actually can happen when you’re multilingual (and is weird as fuck, IMHO) and I do have the feeling that for some people who don’t know me well, me saying “I don’t remember this word in Portuguese” can come out as me being pretentious and showing off my language skills (especially if the word I remember is in a language other than English, since around here and for my generation knowing English isn’t really unusual) when for me it’s almost the opposite and I actually feel that I’m supposed to know it.