6th grade math course switches multiplication symbols inconsistently, and maybe without explanation

I understand that in early math, "×" is used for multiplication, and that there needs to be a switch to "·" by the time variables are introduced because of confusion between "×" and the letter "x".  However, the switch seems to be inconsistent in the 6th grade math course.
The new symbol is explained to the students in Unit 6, Lesson 3 "Why aren't we using the multiplication sign?", but it is already sometimes used as early as Unit 2.

In the Unit 4 Lesson 5 video "Order of operations examples: exponents", "×" was used for multiplication, such as at 0:00 : "2 × 3²".
In the next video "Comparing exponent expressions", "∙" was used for multiplication, such as at 0:41 : "2 ∙ 2 ∙ 2 - 2".
In the video after that "Order of operations example: fractions and exponents", multiplication was implied without a symbol, such as at 3:00 : "(1/14)(1 + 1)²".
Was the change explained anywhere before Unit 4 Lesson 5? I have looked, and cannot find the explanation.

In Unit 2 Lesson 5's "Dividing Fractions Review", both symbols are used on the same page!
Near the top of the review, "×" is used:

Then in Example 2, "·" is used:

I would like to be able to use the appropriate multiplication symbol when responding to Questions, so that the response is most helpful; this would be easier if it were clear at what unit in the course the symbol switch is made.

Does anyone have thoughts or suggestions or information about this?