Cross-reference to paragraph not updating when paragraph moves

[windhoek2010]

I have a document with many sections:

1.1 Section A
1.2 Section B
1.3 Section C



So I inserted a cross-reference to the "paragraph number" and "paragraph text":

For more information see 1.2 Section B.

But when I insert a new Section A2 under Section A:

1.1 Section A
1.2 Section A2
1.3 Section B
1.4 Section C

And I update the cross-reference (Ctrl+A, F9; or right-click cross-reference, Update Field), it does not update. Worse, sometimes Word dumps the entire content of Section B in place of my cross-reference.

My question: What is the "correct" way of inserting new sections, or moving the sections so that the cross-references can be updated correctly?

I'm using Word 2016.