Restoring a "lost" bar line in an 8-beat 4/4 bar

At some point either during editing, or possibly in the original importing of my MIDI data, one bar of my composition was elided. There are supposed to be five bars of 4/4 starting at bar 93, followed by a 3/4 at bar 98:

The special red tag is telling me something, and clearly there are too many beats in the piano part - but the important questions is: How do I add in another bar line in the middle of that mess? Is there a way to tell Dorico to split a bar? Other ideas? Help much appreciated!

-DS

(These are called Signposts)

Try navigating to the rhythmic position that you want the 3/4 to be at and then re-enter the time signature. That should fix it. You will probably also need to delete the following 3/4 time signature to the right of your screenshot.

Just select the barline with the red signpost and hit delete. (This will remove it and allow the previous 4/4 to apply up to the 3/4)