Country borders look very similar to the lifemap, at least to my colour-challenged eyes. In this picture, there are three borders meeting in the middle and one run going through that same point. Country borders in Europe are easy enough to cross that I cannot imagine being the only one to have encountered this.
(I don’t know if this is an easy one to fix, because I vaguely recall you wanted to stick close to the Mapbox default theming, so any change is possibly a pain to maintain)