ConversationItems sometimes not displayed or loaded properly

When opening a conversation sometimes incoming messages are not displayed properly.
The size of the "box" holding the message changes randomly, sometimes it's too small (cutting most or even all of it's content), sometimes it's too big. The same message was displayed with different wrong sizes.
Examples:

1. The frame is too big (there is no newline or anything - I had this one also with the complete content cut)

2. Part of the message cut because the frame is too small

3. Part of the messages cut

4. Messages from 3 shown correctly

(I removed everything else from the images out of privacy reasons)
If you scroll the incorrect item out of view and back in it's being displayed correctly.
Steps to reproduce:

1. Enter a conversation
2. Lock and unlock screen repeatedly until you find a bugged incoming message.