URLs garbled with custom message format spec

First of all complements on the package.
I only started using it at the weekend; indeed, it was only last weekend that I'd even found out about Matrix so I'm still very much new to the whole thing. Nevertheless I'd long wanted to be able to just keep in touch with friends that use the likes of Whatsapp etc., but to do so from Emacs, and now I finally can!

So thank you for the package (and for Burly too!).

Now to the problem I've encountered.
Actually with the default settings there is no problem, but I've set a few variables, namely:

```
(setq ement-room-message-format-spec "%t%L%B%r")
(setq ement-room-sender-headers t)
(setq ement-room-sender-in-headers t)
(setq ement-room-sender-in-left-margin nil)
```

Unfortunately, a consequence of that particular format spec is that URLs don't seem to be getting detected by browse-url correctly - either the timestamp gets interspersed within the URL string or some other garbling occurs.
In any case, the links break. I'm still taken to a browser, but it's only my homepage.