747 Focal and all,
The only triple engine problem I am aware of on the Tay converted 727’s was loss of power on all three engines due to a fuel surge then flameout when all cross feeds were (inadvertently) opened, then boost pumps turned on. Apparently, a situation that would have gone (virtually) unnoticed on a JT-8 powered aircraft is a big deal on Tay aircraft. To my knowledge, the fix is procedural and not a hardware fix – some sort of flow restrictors were tested/proposed, but not incorporated. As I recall, the player is different type of engine driven fuel pumps - Tay vs. JT-8, and their ability to handle (feed) pressure transients.
Haven’t heard about the analog/digital anomaly you refer to. Was this is flight testing, or after certification?