Partial translation bug

Hi,

I’m translating a theme and plugin from english to french with Loco,
all files are located in Loco safe folders, but some words, even though they have been translated remain in english.
I’ve checked the .php files where they are called, and the strings are not hardcoded.
Some words show up in french for a few days, then show up again in english, although the translations are not missing in the .po or .mo files.
I’m lost, is there a cache to clean somewhere to force WP to scan and read again from the freshly translated files ?

Thank you