It's likely that this paragraph from Belgique's linked article (
post 940) will be the operative issue:
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"Overall, it's shades of the previous GE90 "rollback" and IFSD's (inflight shutdowns) from earlier days. The only difference was in those cases, it was in cruise and was caused by moisture freezing in the P3B and PS3 lines to the FADEC, and it was resolved by increasing the tubing diameters."
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Methinks that frozen fuel pressure reference lines identically influencing each FADEC's outputs would stand the best chance of uniformly affecting both engines (for identical reasons - and perhaps related to Beijing's fuel quality and the amount of FSII icing inhibitor included in the fuel uplift being inadequate).
Those reference line thickness parameters are unlikely to differ overmuch between engine types.