Replying to Shingbang only on half of your shin?

So I have some Nordica Ace 3 star boots that I love. My favorite boots I have worn so far. I've had them just over a year now and today was the first time I've had shinbang in them. The shinbang was only in my lower shin however (a few inches up from my ankle). My upper shin where I have always had shinbang with previous boots feels fine.

Anyone know what's up? My guess is that my liners are very packed out and are causing this somehow because my boots feel perfectly fine after 120+ days on them. I have booster straps and crank my boots down as tightly as I can get them without cutting circulation so I know it's not from having loose boots either. I also have custom footbeds and the boots were professionally fitted. Who knows though. Maybe there don't fit me well enough.

I am also open to solutions because I forgot how much shinbang sucks balls.