Stolen Block, Possible?

MYLO was scheduled to mint 3 blocks in epoch 305 as per cncli leader check log (attached). MYLO minted the first 2 but the 3rd block was minted by someone else. How is it possible? I thought if a slot leader goes offline during its schedule, then that block is skipped. Wondering if a block can be stolen.

The block in question is at slot 290969.

As per, that specific slot was minted by LAMB stake pool
Block 6566554 - Cardanoscan

MYLO was online during that specific duration

Check out the this Blog post which explains slot assignment

And the nerd out about slot battles: Cardano: NerdOut Slot Battles - YouTube

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thanks for sharing. Great explanation

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I am still not sure if my issue is related to slot leader battles. Reviewing the logs tell me my BP did what it was supposed to do. There is a TraceNodeIsLeader → TraceForgedBlock → TraceAddBlockEvent → TraceMempoolRemoveTxs → TraceAdoptedBlock events.

Was my block not propagated in time? This issue happened twice in 2 epochs 305 & 306 around the same time, when one my relays (nearest to BP relay ) is rebooting after a topology update. This is the only pattern I have identified. It happened when the nearest relay was down.

did u checked inside the logs what is the output for that slot? It should tell u if the block was stollen or not

or if u are using cncli then run init and it will tell you what happened with the block

This is your block shown on cncli leaderlog but as u can see it was minted by another pool (VRF battle)

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Yes, the log shows that my BP minted it. This issue happened again on epoch 306 at slot 117335. NFTY minted it instead of MYLO but cncli said I am suppose to mint it. Attached is the relevant log output from BP

This is troubling

Of course both pools minted the block but it was accepted only the block with the smallest VRF


In a slot battle, I thought the one with the smallest stake wins and that would be MYLO. However NFTY won. VRF key is constant for each pool, so didn’t understand what you mean by smallest VRF.

MYLO has a VRF, CHRTY has a VRF, NFTY has a vrf

if MYLO and NFTY have the same block assigned then the POOL with the smallest VRF will win the slot battle, in this case NFTY

I think the smaller VRF is not guaranteed to win a battle. It just has a higher chance.

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That may very well be in my case.