In the verse we see the word וִיהִי. It has the waw consecutive and is Qal Jussive 3ms. But I would of expected וַיְהִי (just like in verse 1:5, but in 1:5 it isn't the Jussive but the 'normal' imperfect).
I think it's because of the accent that falls on the waw.
There is a little vertical line called "meteg" מתג that indicates a secondary accent.
Watch how the words are accentuated: ויהי-בקר (without the bar in the bible) בקר the accent falls on the first syllable there for the accent withdraws in ויהי.
In hebrew it's calld נסוג אחור =withdraw back (the accent).
So the W in the ויהי in 1:6 is a regular W (just like any other W that is written with Sheva)
But here, since the vowel of the letter Y of ויהי is already with Sheva
יְהִי
and then, we expect that the prefix W would come also with Sheva (as regular).
Then in this case of Sheva-Prefix-W before a Sheva-Y --->
the W is voweled with Hiriq, and the Y looses its vowel and becomes silent.
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Read the translations for this verse and for 1:5, and see the differences of the ויהי in the verses.
Remember that you cannot have two vocal shevas side-by-side. One will resolve into a full vowel, usually a chirik, which is what happened here. When yod finds itself in the position with chirik before it and sheva on it, it becomes a vowel letter. The same thing happens in phrases like:
Notice that "from Jerusalem" also shows the dropping of the dagesh due to the "Skinemlevy" rule. That is, when any of the letters {שס}קנמלוי (sin/shin, samech, nun, mem, lamed, vav, or yod) have dagesh and are followed by a sheva, they will tend to lose the dagesh. This is also what happens in words like מְבַקְשִׁים in which the middle radical is normally doubled (מְבַקְּשִׁים), but it regularly drops out with a Skinemlevy letter.
So, the word in question is not vav-consecutive (which has patach and dagesh with the vav). The vav-consecutive works like this instead:
thanxs everyone!! Thanxs also for bringing "back to my memory" that "no word can start with two shevas" (but I didn't remember that ha-ha, nor what one does when you have that situation).
OK, so that's a normal "conjunction" and NOT a waw-consecutive - it makes sense now.