Freqently getting early base defense missions

[Dioxine]

there's not. the base has to be discovered first.

Then Meridian describes a really strange behaviour.

[Meridian]

Then Meridian describes a really strange behaviour.

I think I may have found an explanation.

I had a lot of retaliation missions a game-month ago or so. I deleted all of them from the saved game, because they were irritating me like hell.
But I think that's not enough... there is a flag called "retaliationTarget" on xcom bases in the save... and this was "true" for two bases (Canadian and Brazilian).
I think (not confirmed) that it means that the base was already found and will be targeted soon.
Since I've deleted the missions, it couldn't be targeted however.

Now, after I shot a UFO near Brazil, a *new* retaliation mission was generated in that region... but my Brazilian base was "already discovered" by the previous mission, which I've deleted...
and thus it spawned a battleship directly.

At least that's what I think.
I have reloaded and replayed that particular bit many times, sent dozens of ships to patrol in addition to hyperwave decoder, but I couldn't detect any scout.
So I'll go with that explanation for now.

[SupSuper]

I think I may have found an explanation.

I had a lot of retaliation missions a game-month ago or so. I deleted all of them from the saved game, because they were irritating me like hell.
But I think that's not enough... there is a flag called "retaliationTarget" on xcom bases in the save... and this was "true" for two bases (Canadian and Brazilian).
I think (not confirmed) that it means that the base was already found and will be targeted soon.
Since I've deleted the missions, it couldn't be targeted however.

Now, after I shot a UFO near Brazil, a *new* retaliation mission was generated in that region... but my Brazilian base was "already discovered" by the previous mission, which I've deleted...
and thus it spawned a battleship directly.

At least that's what I think.
I have reloaded and replayed that particular bit many times, sent dozens of ships to patrol in addition to hyperwave decoder, but I couldn't detect any scout.
So I'll go with that explanation for now.

That is correct. When a base is detected by a retaliation UFO it gets flagged, and any retaliation missions on a region with detected bases will immediately target them, otherwise they will just scout.
Just having detected bases does not trigger a mission though, it's the other way around. "Oh a retaliation mission spawned, and we happen to know about this detected base, why waste time?"