When chatting on the Android app (and potentially iOS), not all text is displayed for multiline messages.
This bug seems somewhat difficult to reproduce consistently. Some messages seem to display fine while others do not. You can attempt to reproduce it by sending a message that should be on multiple lines to another user.
The message sent by me in the screenshot reads
I think the app might be culling your messages
Version: 2.317.167174
Device: OnePlus 3T