Update: F2Pool included their first P2TR spend (mempool.space/tx/414ef7844f2…) today in block 710269. F2Pool reached out, and we debugged the issue: Nodes are up-to-date but didn't have any >=v0.21.1 peers (due to custom patches and addnode) that relayed P2TR spends. That's fixed now.
Looking at the pools that mined more than 3 blocks since taproot activation or included a P2TR spend, it's clear that F2Pool and AntPool are, very likely, NOT including P2TR spends. F2Pool already mentioned that they will upgrade their infrastructure soon.

Nov 18, 2021 · 5:56 PM UTC

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AntPool might have a similar problem. Apparently, their nodes are up-to-date and the peers too old, too (I don't know details). @bitentrepreneur has been in contact with them 🙏
antpool should be incl. P2TR very soon (hopefully, tomorrow)
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The blocksize war made this a sensitive topic. From what I've seen so far, I personally don't think anyone was or is acting in bad faith when initially not including P2TR spends. Let's see how this plays out over the next few weeks.
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What was the fix btw? Was it just updating the peers?
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Connecting to up-to-date nodes, yes
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Any bugs to report / possible patches that might help avoid this issue in future?
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IMO: Can't really protect against running custom software. In this case, up-streaming the patch does not make sense. I'd rather not publish details. What might have helped: Is there a way of testing relay before activation or signaling even (I don't think there is)?
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