infinitymdm I just haven't cared enough to bother looking for a fix yet.
Same here. I've reproduced it in a VBox VM with both GNOME terminal and Terminology. But it hasn't risen to the level of an annoyance for me. At least, not one that's serious enough to require researching a fix.
To be honest, that may be because I use the VM for very limited testing purposes. 99.99% of the time I'm using Plasma, where I could not reproduce this result. Repeating the experiment on my Plasma laptop produced this:
It doesn't matter whether it's my laptop or a Plasma VM, or whether it's konsole or Terminology, if I slowly push the bottom of the window up, before it gets close to the descenders, the window's contents pop up, leaving almost a completely empty line below.
Whether it's the DE, or the terminal application, or something else, I don't know. But apparently switching to Plasma instead of Budgie would solve the problem.