Excerpt from `help until`:
"Execute until the program reaches a source line greater than the current"
It very clearly states 'source line', however in practice when executed at the last line of the body of a C `for` or `while` statement, it will jump back at the head and break there. This even happens if the increment field of the head is empty (there is no operation executed after the last line of the body on a technicality).

On the other hand it works as one would imagine when used on the footer of a do-while loop.

I suspect it's a bug and not intended behaviour, otherwise, the help message is still misleading.