Compound Wall Cleanup

[Henry D]

I have this Basement wall composed of 10" conc. and 2x4 furring w/ drywall. I can't get it to cleanup at the corners. If I use the same wall type in another file it does cleanup. Why might they not be cleaning up in this file?

Thanks a lot

[Henry D]

I got them to clean up using the edit wall joins command. I'm still trying to figure out why they were fine when I initially drew them but later became unjoined. Do compound walls tend to unjoin when they get vertically edited?