AFAIK, there was no swapping batteries in Europe either, during the "crisis". All batteries were declared not-airworthy. The sailplanes could only fly as pure gliders.
I was deeply impressed by how short has been the time it took Luka to analyze the faults and then provide a solution, then have it approved by the authorities and finally return the FES systems to service.

There are so many examples of much longer delays, lasting up to many years, for relatively simpler problems like (for example) the propeller hub failures on the Solo 2350C engine system as fitted to Antares and DG1000T.

In many if not all aspects, auxiliary powered gliding has always been a bag of problems. That said, all my sailplanes are/were fitted with engines.

Aldo Cernezzi