I have twin 525s and when I run over 4700 rpms for 5-6 miles one or the other will out of nowhere return to idle. I can bring it down to idle go to neutral then back in gear and works just fine. If anyone has an idea on what the problem is I would love to know

you getting any alarms? Any fault codes?

Happen to have a single line feeding both?

Does it do it again or just the one time?

No it happens at random time twice on port once on starboard on separate lines

As imartin mentioned, any alarm?

Do you hear beeps when key is turned ON prior to start?

What's the engine serial number?