# Optimistic mining tip (slow block propagation)

**URL:** <https://delvingbitcoin.org/t/optimistic-mining-tip-slow-block-propagation/2139>\
**Category:** Implementation\
**Tags:** bitcoin-core, mining\
**Created:** [December 3, 2025, 10:41am UTC](https://delvingbitcoin.org/t/optimistic-mining-tip-slow-block-propagation/2139 "2025-12-03T10:41:11Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![optout](https://delvingbitcoin.org/user_avatar/delvingbitcoin.org/optout/32/1693_2.png) [@optout](https://delvingbitcoin.org/u/optout)\
**Post date:** [December 5, 2025, 9:11am UTC](https://delvingbitcoin.org/t/optimistic-mining-tip-slow-block-propagation/2139/4 "2025-12-05T09:11:56Z")

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Thanks for the explanation and links, Bob & Antoine (P)! I have simply overlooked the fact that block validation is more than the act of validation of the block itself, but it also includes the updating of the state: UTXO set, etc. It’s not surprise that this is an issue that came up often during the history of bitcoin (I was not aware of the details). It’s a fun fact that Gregory Maxwell’s verification flag proposal was exactly 10 years old yesterday!

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