[Zeke]

^^^^that would be one way to do it and fairly traditional in some parts of the country.

For sure, the gaps invite little guests that one might not want in there. Another solution is to cut some small wedges out of some inert material like AZEK or Trex decking of a similar color.

I'm sure there is step flashing above and that could have been continued albeit modified once it passed the end of the wall.