Oh, looking at that screenshot its LD (Local Deployment) and MA (Multi Attack).
Did you complete your entire starting island at the end of turn 1?
Because it doesn't look like it, so keep in mind that with MA, you can keep attacking with the same armies.
I'm not sober enough atm to properly explain that, so see
https://www.warzone.com/wiki/Multi_Attack and hope its understandable.
Perhaps try it out first on
https://www.warzone.com/SinglePlayer?Level=1311287A play-trough of someone else (
https://www.youtube.com/watch?v=twRD1m4Zx58) show the AI with the big stack being less aggressive there, (at least in the earlier turns), so idk whats up with this without being able to play the levels myself.