Double posting

### Site

dev.phanpy.social

### Instance

mastodon.social

### Browser

Zen Browser 1.17.15b (Firefox 146.0.1) (aarch64)

### Bug description

When publishing a post, the interface displays an error: "The server returned data with an unknown encoding. The server may be down." Immediately after this error, the post appears twice in the timeline without any additional clicking or retries from the user.

### To reproduce

Not always reproducible, but I've hit this 3 times for last 10 days

1. Compose a post.
2. Press "Publish".
3. Observe the "unknown encoding" error message.
4. Check the timeline/profile to find that the post was actually published (two times) despite the error.