US mobilization drops without cause by november/december 1939

[Treefrog]

in 1939 campaign game US mobilization starts at 22% and then without discernible reason drops in my various games to range 16% to 19% by November/December 1939.

No events are triggered. Review of graphs show no Axis diplomatic activity. No US units change location to offend isolationists.

Why does this unexplained drop[&:] happen?

[Xsillione]

Winter war and the Irish ports are the two event around that time that can reduce the US mobilization.

[Treefrog]

thank you xsillione.

anybody identify any others?

[Helsingor]

Well, if France and the UK launch a preemptive attack on Italy, US mobilization will drop. Playing as Allies, I did it once, but only because I had a chance to hit several Italian warships and also some transports as my opponent was trying to slip some units through the Straits of Gibraltar