When player is speaking with Octavia and the camera moves to Ulpius who is preparing to jump, there is a "press E to speak to Octavia" prompt and my mouse cursor disappears for all the dialogue options so I need to use arrow keys and enter keys to select them.

Hi there, thanks for reporting your issue, and sorry you've had this experience.

I've added your report to our list to investigate, I'm glad you were able to figure out a workaround for it!

https://youtu.be/mH6ehuBuKu8?t=7425

^ Link to my playthrough showing the bug, also happens to me every other time I go into this event in the game