Firefox is constantly changing "http" to "https" for i2p sites

I've configured my i2pd proxy correctly so things are somewhat working. I was able to visit notbob.i2p. But sometimes Firefox really likes to replace "http" with "https" when I click on a link or even enter the URL manually into the bar. I have "HTTPS-only mode" turned off, and I also have "browser.fixup.fallback-to-https" set to "false" and "network.stricttransportsecurity.preloadlist" to false.

I tried spying on the HTTP traffic in web dev tools, and I see the request gets NS_ERROR_UNKNOWN_HOST. This does not happen when using the xh CLI HTTP client, so Firefox is doing something weird with name resolution. I made sure to turn off the Firefox DNS over HTTPs setting as well, but it didn't seem to make a difference.

I assume that name resolution needs to happen in i2pd. How can I force Firefox to let that happen?

Update: Chrome works fine.

Update: I started fresh and simplified the setup and it seems fixed. I'm not entirely sure why. The only things I've changed from default are DoH and the manual HTTP proxy.