Bar split between systems

I have got a bar that is split between two systems, which I don’t want, and am looking for a way to fix it. It came about when I entered a time signature in a single staff (to force a particular beaming pattern) which left that staff with different barlines to the others; but even after I entered time signatures of the same total duration in all staves, so that the barlines coincide, the last quarter note of the bar remains on the next system. If there were a system break flag I could just move it, but there is none. I would rather not enter system breaks at this stage as I don’t want to anticipate casting-off decisions. Is there any way to fix this?

Can you please attach the project, or at least one layout from it? Then I can tell you what you should do in the full project.

Thanks Daniel. I don’t want to post the project here, so I’ll send it to you direct.
I have actually finished and formatted the flow in question and of course the anomaly disappeared then, but it reappeared when I deleted all the frame and system breaks.

The problem was caused by having, momentarily, barlines differing between the staves, when the local time signature was inserted. To Dorico this implied open metre, allowing bars to be split at any point, and even when the barlines coincided again it didn’t repair the split. The cure was to first insert a normal time signature in the rogue bar, which removes the split, and then insert local TSs of the same duration as required (for beaming, note grouping etc.).

Thanks Daniel for quick help offline!