Likely due to the new (and much improved) memory accounting, we seem to have a broken the vb_active_ht_memory statistic. Even up to 1M items in a single node, it has not changed from 25673728.
This is a problem because the "metadata" information in our UI is tracking this stat and is now not accurate. We should either change the stat that is being tracked (I believe ep_overhead might be more appropriate?) or fix vb_active_ht_memory to be accurate.