Why do Expert monsters get Will saves instead of Reflex?

Question

The Starjammer SRD page about building monsters has a chart for Expert creatures. That chart claims that expert creatures should have good Will saves instead of Reflex. Why would that be? Expert style classes (Envoy, Operative) in Starfinder, they usually have good Reflex saves.

Why would this be the case mechanically or thematically? Is it an error?

Disclaimers:

• I'm talking about Paizo's Starfinder, not Starjammer, if there's a difference.
• I don't have Alien Archive to look at, so I don't know if that explains it anywhere or if it's an error.
• I'm reading this from the Starjammer SRD
• I'm talking about building monsters, not existing stat blocks.
• It seems that AON shows the same data

Answer 1

Those are merely baseline suggestions.

The Expert Array, as you said, is best suited for sneaky characters, like envoys and operatives.

Expert Array: Pick the expert array for skilled enemies such as stealthy scouts or noncombatants such as merchants or advisors. The expert array is also used for the envoy, mechanic, and operative class grafts. Expert NPCs benefit from a wide array of skills, making them competent at specialized tasks such as sneaking or sabotage.

But later we see that the GM may freely swap the saving throws:

EAC, KAC, and Saving Throw Bonuses: Use the listed numbers for your NPC’s EAC; KAC; and Fortitude, Reflex, and Will saving throw bonuses. If it would be thematically more appropriate to switch the saving throw numbers around, you can swap them (giving a combatant a low Reflex save and high Will save, for example).

Personally, I would leave the Expert Array with good reflexes by default, but the devs were probably thinking that those kind of monsters would be really hard to beat for most parties and that probably wasn't going to be fun for everybody. Afterall, Starfinder classes have a lot of reflex-based abilities.