Might I humbly suggest that graphically extending vertical lines to span a certain number of staves, and then changing that number of staves by enabling condensing, means the staves were not in their final state. Condensed vs uncondensed staves are 2 different things, and local properties can be different between them, therefore it’s generally best to leave precise changes until everything else is sorted to reduce the amount of duplicate work required.
Unfortunately lines aren’t condensed yet. In your case, where you’re wanting staves to span multiple staves, an alternative approach might well be best regardless, as already alluded to.