Gizmos.DrawCube bug? Doesn't like lots of calls.

I’ve noticed that whenever Gizmos.DrawCube is used a lot, it stop drawing cubes and starts drawing a bunch of random lines. See screen shots below. Through some testing I’ve discovered that the magic limit is 1365. For example, if I make a grid of 10x100 cubes (1000 total), they all draw correctly. But if I try to draw a 10x100 grid of cubes, they start getting messed up. Is this a bug?

(10x100 cubes, everything’s okay)

(100x100 cubes, barf…)

This might be due to Unity’s max vertex count per object, which is 2^16 (65536) and 100*100 cubes is 10 000 * 8 vertex, 80 000. If this is incorrect, I’ll move my answer to the comments.