In the seventh aliyah of Parshat Noach, the passage about the tower of Bavel contains the phrase עַל-פְּנֵי כָל-הָאָרֶץ three times. Twice it is written כָל and once כָּל and I would like to understand the difference.
I know that the presence or absence of a dageish depends (among things) on the syllable that comes before, which in this case is the end of the previous word. It's the same previous word all three times. And I understand that sometimes rules change at the end of a sentence (e.g. gafen versus gefen), but two of these are at the end of a pasuk and the third is at an etnachta (basically a semicolon; a clause if not a sentence). Is there some other grammatical rule in play, or is this just a quirk of the torah text as we have it, like we have with some hus that are read hi and bigger ktiv/kri'a differences?