Messages in spark appears in blank

Hi, I´ve a problem, when someone sends me a message, I can´t see the message sent, appears in blank. The version of spark is 2.6.3, can you help me?

I have this issue too, we have ~250 users, this happens maybe… once every two or three months. Only solution that we know of is to reinstall the client and manually remove the users %appdata%\spark directory. Also using 2.6.3.

It’s a known bug in older Spark versions. Upgrading is the only long-term fix.