Online keyboard stops working after selecting file to send

I use the flatpak provided by Elagost on my Librem 5. Version 5.30.0. I am not sure where to report the issue let me know if this is not the correct place.

Description:

1. Open Signal Desktop
2. Select a conversation (e.g. Note to self)
3. Tap the + sign at the bottom right
4. Select a file (I tested with a .jpg)
5. Tap the Open button at the top right (the file is shown in the conversation)
6. Tap the text box at the bottom to start entering text
7. Make sure the online keyboard is visible by clicking on the keyboard at the very bottom right, outside of Signal.
8. Start tapping keys on the keyboard

Expected behavior: The tapped keys appear in the text box and the -key sends the message with the file attached.

Actual behaviour: The tapped keys are not accepted by Signal.