Something wrong with time signature.

Hi, In my score I change from 4/4 to 3/4 time, so I dragged the 3/4 time signature to the new bar and that was fine. But in completing the 4/4 bar before it, all of a sudden I got garbage in the 3/4 bar. The bar in the bass clef now shows only one beat in the bar, where the staves above it show something else, and I've got the time signature 3/4 appearing all over the place, and there is garbage (looks like a second voice, but only a rest) in the baritone solo line, which I didn't put there at any point. Can anyone explain what's going on here, and how to fix it? Thanks in advance.