Map not updating when entering area

Expected behaviour:
All maps updating properly when I enter the area they're mapping.

Actual behaviour:
The first map pretended I was still outside the area (didn't chart new terrain and didn't update marker; resolved after relogging).
The second map retained a marker at the place I had previously left it and created a new one as I entered its area again (stuck marker still there after relogging).

I had two maps (both zoomed out all the way), one perfectly adjacent to the other (which is what I was trying to achieve). When I left one of them and entered the other, the map I was now on did not change the white indicator from a circle to an arrow and new terrain was not being mapped. After relogging, it was fixed, the map was showing the white arrow and the terrain that I had previously visited was now charted too. However, when I left that map again and entered the other, the white indicator that had been there from the first visit did not disappear, a new one was simply added. But this time, I was able to explore new terrain and have it added to the map. The old marker didn't disappear, even after I logged out and back in.