Whenever the height of the text inside the description part of the bug report window is less than the available height of the window, scrolling will be disabled. Whenever this happens however, there is no guarantee that all the text is actually inside the viewing window.
Reproduction steps:
1. Type a text that is shorter than the viewing window
2. Add a few newlines to the end of this text
3. Remove these empty lines again, such that all available text once again fits within the window (note that removing lines at the bottom of the text window does not make the text auto-scroll upwards, thus showing additional post-text whitespace at the bottom)
What can be observed now, is that the text is still in the scrolled-down state, thus having the top text not readable. Since the window however realises the required height is less than the available height, the scrolling is locked to the current position anyway. To see the text at the top, the user will either have to type more text first to make the window re-enable scrolling, or move their cursor upwards.