Are they not on power-by-the-hour, and thus it's Engine Alliance's problem to pay the bills for a replacement ?
depends on the fine print. Typically the costs associated with operating an airline, e.g. diversions, delays, cancellations and insurance are an operators responsibility.
A manufacturer may use his own experience in associated cost of parts and replacements in the support. I don't know the fine print in a specific contract relating to repair logistics, thus my questions.
anybody got any info on what broke and why? all I know is what's missing