If multiple engines do the same thing when attempting this, it seems something isn't right.
Have you tried selecting the lash up and starting it up that way, making sure you have not selected the lead engine somehow? (If that doesn't work, for a test what happens if you delete the lash up and reverse the two engines?) Once in a while we have had lash ups with horn and bell in both engines, no idea why, the others only head light and coupler work on trailing engine.
DCS level and engine numbers? One TIU?
