Do you have a language selected at the game’s main menu, so the .exe starts up in that language? Or is still in English, and you have to Ctrl+T and select a different language each time you log in?
Gifts are disabled, so maybe this is causing your impression.
I have discovered a scenario where your translation changes will be reverted for a period of 3 minutes. This only affects text sent by the server (e.g.: Inbox messages, Galactic/Regional Store descriptions, custom “disabled button” text). It does not affect text that the client uses directly (e.g.: anything shown in-mission, tutorials, button captions)
Could this scenario be applicable in your case? Do you remember what the “lost” phrases were?
Next time you notice this happening, please (i) report the exact phrase that was lost and (ii) wait 3-4 minutes to see if it fixes the issue.
Recall that text in the Inbox is baked-in and won’t automatically update until you receive a fresh message.
When joining a multiplayer game mid-wave, can you somehow show the name of the current wave shortly? Though there was a invulnerable time, sometimes it’s not enough to notice what wave was it to prepare. Imagine you’ve just join in the Henperor’s Apprentice boss and get hit from behind because you didn’t realize what wave was it quick enough.