Pool fee information shown can be misleading

[hodlonaut]

Steps to reproduce the issue:

1. Register stake pool with 0% variable fee
2. Wait for pool to appear in Daedalus wallet
3. Near the end of the epoch modify the pool and change variable fee to 50% - a few minutes later Daedalus will show pool fee as 50%
4. Wait for epoch boundary and snapshot, then half an hour into new epoch modify the pool and change variable fee to 0% - a few minutes later Daedalus will show fee as 0%.
5. Rinse and repeat steps 3 and 4 as much as you like

So while Daedalus will continue showing the fee as 0% for almost entirety of the existence of the above-described pool, in fact the snapshots of the pool state will be capturing 50% variable fee and soon enough delegators to this pool will start seeing drastically reduced rewards.

Correct behaviour would be to show the snapshotted fee value from the last epoch boundary in Daedalus - currently a couple of the community tools/explorers are doing something along these lines (pooltool.io, cardanoscan.io). Showing scheduled-but-not-in-effect fee value is incorrectly lulling delegators into a false sense of security in the above scenario.

Once Daedalus side of this issue is resolved, it would be good to check with ledger state team to make sure similar set of steps doesn't cause a loophole of some kind in the estimated pool rewards / rankings (it's possible they are already catering for this and pool will already be demoted to a lower ranking after the epoch boundary/snapshot - i haven't had a chance to test that on a testnet Daedalus yet as epochs are quite long).

[nikolaglumac]

Daedalus gets this information from the CWB. So this is more of a question for the Adrestia team.
What do you think @rvl ?

[dmitrii-gaico]

@hodlonaut Hello. Can I kindly ask you to advice if the issue you reported is still reproducible. If so could you please create the same card/report under the "cardano-wallet" repo mentioned by Nikola. Thank you in advance!