I think quite a few aircraft types do similar things to this. When you think of all the sloshing around, density gradients, sensor tolerances, etc. it’s a wonder they’re as accurate as they are.
If I was designing one I think I’d err on the side of caution and display the lowest sensible reading that you could get from the raw data. The 777 seems to work that way as I’ve often seen a “dip” mid-flight but never excess. It does seem to get much more accurate as the fuel amount reduces, which on reflection is probably the best way round...