The blue circles are Leaflet's default style when no style is set in the code. This has happened because your QGIS layer renderer doesn't have an entry for your non-"nit" points.
To solve this, we need to know which kind of renderer the point layer is using in QGIS (eg categorized? rule-based?). You need to add an extra category/rule accordingly which covers your other points, and then style the symbol for it appropriately (such as with full transparency to hide it).
I hope this is clear enough - if you can edit your question to include the point layer renderer type, I can make this answer simpler and clearer (hopefully).