Hi there,
I've been using this mod for the longest time and never had any issues with it. Not sure when this problem appeared (I didnt play factorio for a while) but now the nixie tube display no longer works properly... The actual number is sometime inaccurate, missing the last digit or simply won`t update. Also, digits are sometimes shown in gray instead of the usual orange. Leaving the game and re-opening it will often cause the issue it seems. You can temporarily fix the issue by redoing the wiring but this is really annoying.
I tried uninstalling all of my other mods, leaving only the creative mod to test it out, and I still had issues with it.
Let me know if you want a screenshot or more information, I hope we can resolve this as this mod is one of my favorite.