Which Ketores is the Pasuk referring to?
Ramban: "Lifnei ha''Eidus" refers to the Kerores on Yom Kipur 1 and "be'Ohel Mo'ed" to the daily Ketores, when the Kohen brought it on the Mizbe'ach ha'Zahav.
Rashi: It refers to the daily Ketores. 2
What is the significance of the phrase "Asher Iva'ed l'cha Shamah"?
Rashi: Whenever Hashem fixed a time to communicate with Moshe, it was always in the Ohel Mo'ed. 1
Oznayim la'Torah: The Torah sees fit to mention it because, bearing in mind that this Parshah was said before the Chet ha'Eigel, and, knowing that after the sin, Moshe would take the Ohel Mo'ed and move it outside the camp, Hashem needed to specify that, although the new meeting-place was in Moshe's Ohel Mo'ed, the Mishkan was still called 'Ohel Mo'ed', because, although the people did not meet there, it was the location where Hashem would meet with Moshe.
Which is precisely why it was called 'Ohel Mo'ed - 'the Tent of Meeting'.
Why does the Torah not mention the Mizbe'ach ha'Ketores - on which they brought the Ketores?