Kernel exported objects and clist sizes still growing after u18

[mhofman]

Describe the bug

u18 solved a few known (and large) distributed object leaks, mostly related to price feeds. After u18 landed we saw the growth of known kernel objects and clist sizes greatly slow down, but it is still growing over time, albeit much slower.

To Reproduce

Observed known kernel object counts and clist sizes on mainnet

Expected behavior

Flat graphs. There is no reason for any distributed object reference to accumulate.

Platform Environment

Mainnet running u18

Screenshots

https://monitor.agoric.net/d/cdzujrg5sxvy8f/agoric-chain-metrics?var-cluster=puffynet&var-namespace=followmain&var-chain_id=agoric-3&orgId=1&from=2025-01-10T13:37:33.000Z&to=2025-01-14T04:37:33.000Z