place for .mo and .po files

Where should I put .mo and .po files to not be overridden by plugin updates? I tried in wp-content/languages, wp-content/languages/plugins and my_theme/languages? Nothing seems to work, every time it uses wp-glossary/lang mo and po files.

I need that because I have a problem with glossary, WPML and permalinks. In german the nav bellow shows previous and next links like …de/W?rterverzeichnis/myterm. WPML is giving it …de/glossary/myterm/. Or that is what I imagine is the problem. When I translate W?rterverzeichnis as glossary everything works just fine.

I’m open to other suggestions too.

https://www.ads-software.com/plugins/wp-glossary/