Regarding The Frozen Reaches invasion mechanics, it states that units lose Strength at the end of each Phase of the invasion.

My question is: If a unit such as Sphinx heavy guard are Strength 10, and receive a bonus of 10 Strength when engaged in Offensive Operations, does this mean I subtract their losses from 20, or 10?

It seems if I'm subtracting from their bonus amount, they never really are in any danger of being destroyed (2d5+2 being the worst losses they can suffer, meaning a a total of 11 or 12 is needed to actually hurt them).

10 is their actual Strength, so subtract from that. The bonus represents their skill and equipment.

Thanks for the fast reply

Is this what you have figured out personally, or have the developers answered this question elsewhere?

Simple logic and familiarity with the peculiarities of how FFG phrase things, mainly.