We typically do say in English that we go somewhere at 'one' or 'two', etc. No need to add the 'o'clock' but this was not accepted here.
You can always report this thing as a problem rather than "discussing" it. That's the better way to reach people who can actually fix it. There's also software in place to track the number of reports made.
Could this also mean "on the first (of a month)" rather than "at 1 o'clock"?
Not without a strong context suggesting that.
If we allow for a strong context suggesting something, it could mean just about anything. "My wife will go to a restaurant at the first sign that I won't help with the dishes."
This is so strange, because male voice is saying this :D