Can two directly peered Bitcoin nodes temporarily diverge to different chain chips?

Suppose two Bitcoin nodes A and B are directly peered and each has an additional peer.

A → B, C, D

B → A, E, F

Assume that both nodes are currently in block X.

Now imagine that two miners produce competing blocks Y and Z of the same height. Block Y reaches node A first (via C) and block Z first reaches node B (via E). While A is validating Y, B is validating Z, and the result is:

Node A: X ← Y

Node B: X ← Z

Blocks Y and Z have equal difficulty, so the amount of work on both chains is the same. Now, when nodes A and B exchange blocks Y and Z, do they update their chips, or do they just hold those blocks until one chain is longer than the other?