I lead the DeepMind mechanistic interpretability team
Fun post! Note that you can see the diagrams here https://web.archive.org/web/20220523235545/https://markxu.com/dropping-out
I got the OpenPhil grant only after the other grant went through (and wasn't thinking much about OpenPhil when I applied for the other grant). I never thought to inform the other grant maker after I got the OpenPhil grant, which maybe I should have in hindsight out of courtesy?
This was covering some salary for a fixed period of research, partially retroactive, after an FTX grant fell through. So I guess I didn't have use for more than X, in some sense (I'm always happy to be paid a higher salary! But I wouldn't have worked for a longer period of time, so I would have felt a bit weird about the situation)
Without any context on this situation, I can totally imagine worlds where this is reasonable behaviour, though perhaps poorly communicated, especially if SFF didn't know they had OpenPhil funding. I personally had a grant from OpenPhil approved for X, but in the meantime had another grantmaker give me a smaller grant for y < X, and OpenPhil agreed to instead fund me for X - y, which I thought was extremely reasonable.
In theory, you can imagine OpenPhil wanting to fund their "fair share" of a project, evenly split across all other interested grantmakers. But it seems harmful and inefficient to wait for other grantmakers to confirm or deny, so "I'll give you 100%, but lower that to 50% if another grantmaker is later willing to go in as well" seems a more efficient version.
I can also imagine that they eg think a project is good if funded up to $100K, but worse if funded up to $200K (eg that they'd try to scale too fast, as has happened with multiple AI Safety projects that I know of!). If OpenPhil funds $100K, and the counterfactual is $0, that's a good grant. But if SFF also provides $100K, that totally changes the terms, and now OpenPhil's grant is actively negative (from their perspective).
I don't know what the right social norms here are, and I can see various bad effects on the ecosystem from this behaviour in general - incentivising grantees to be dishonest about whether they have other funding, disincentivising other grantmakers from funding anything they think OpenPhil might fund, etc. I think Habryka's suggestion of funging, but not to 100% seems reasonable and probably better to me.
Strong +1 to this! Also, entertainingly, I know many of the people in the first episode, and they seemed significantly funnier there than they do in real life - clearly I'm not hanging out with you all in the right settings!