Customized barline spans not always overriden when extending staff barline span
This is related to #287613: Set to staff default only affects first selected barline
Create the score from the Classical Orchestra as in #287613: Set to staff default only affects first selected barline
Select the first 2 measures of 3 consecutive instruments, like the Flute, oboe and Clarinet.
Right click the barline and chose Select all similar items in Range selection.
Remove the check from "Span to next staff"
Click "Set as staff default"
As in the other bug report, the barlines are only shortened in the top staff (Flute)
Double click a barline on the flute and drag it below the clarinet. All of the barlines are connected except the barline you previously selected that should extend from the Oboe to the Clarinet. The way to fix this is to select the short barline and check "Span to next staff"