This may be what you call manual, but in Write mode place the caret at the location of the missing bar line, and then type SHIFT+B plus the pipe (|) character–without the parentheses, of course.
There is another interesting barline behaviour. In a recent project I’d added a double thin barline but later decided that it wasn’t necessary. When I selected it, invoked the barline popover and typed ‘|’ it reinstated the single barline but it also added a signpost for an invisible time signature which was impossible to remove. I ended up undoing the barline change and simply selecting the double thin barline and deleting that. It reinstated the single barline. Any idea what that’s about?
It’s essentially a barline “override” - you can select the barline and delete it (the barline, not the signpost). You can also just select e.g. the double-thin barline and delete it, and it will be replaced by the default normal barline.