As reported by @bb and @Angen , rP23925 broke formation walking in a few situations.

The issue is that rP23867/D2871 requires formation members to get no messages until the controller is stopped, but rP23925 didn't use the correct function (on account of a missed rebase), so members stopped too early.

Notice that formations now work correctly, particularly in two situations:

• Creating a formation on any skirmish start and ordering units to move.
• Running into an obstruction.