[2020] Unit rosters are sometime not locking correctly in Grand Arena

DESCRIPTION:

• Players can sometimes have their roster locked at a different times than other players
• Sometimes mods and new units can be updated in Grand Arena after lock

REPORT: https://answers.ea.com/t5/Bug-Reports/Using-NEW-Character-after-setting-up-GA-Defense/m-p/8033686#M29739

Ticket # 78423