I have seen similiar behavior, but not this particular case. We create a new version of our termbase every month and of course with a new termbase, the hitlist settings from the old are lost. I have to set them up again and then I save the settings because Studio will inevitably not remember them the first few days of the month, in which case I load my hitlist settings. At some random point, usually just after 1-2 days, Studio picks up the plot again and remembers them. Until then, I just reload my hitlist settings file, just takes a second. I've never experienced where they disappear between units, however. Nevertheless, maybe saving and reloading once or twice (or loading, closing Studio and reopening) will help.