Fuel flow operating conditions that produce "anomalies", are usually the result of something physical that can move around in the fuel system - or there's a physical fuel flow impediment that only raises its head under specific conditions.
As an example, many decades ago, I was travelling with an older brother and he was driving an old International truck that belonged to his boss, a builder. The truck started and ran fine, and went well for most of the trip until we ran into some hilly country.
Upon the need to have maximum power from the engine, it started to show signs of fuel starvation - to the point eventually, where it wouldn't climb one relatively small hill. The brother suspected a fuel supply problem, and as he was quite good mechanically despite being only a young man, he promptly removed the main fuel line from the fuel tank, found some fencing wire, and poked it up the fuel line.
To our amazement, a piece of circular thin plate, virtually shaped like a carburettor butterfly, fell out of the end of the (steel) fuel line. This tiny piece of plate appeared to be the centre remnant from a hole punching machine.
It immediately became obvious, that being a neat fit in the fuel line, when it went up the line, it was initially moving with its body parallel to the line. Then it must have reached a restriction point where it was turning at 90° to the line and effectively shutting off the fuel supply, like a tiny shutoff valve. We replaced the cleaned fuel line, and the problem was solved.
I'd suggest it's possible there's a manufacturing obstruction in the fuel system, that is creating intereference in the fuel flow when it reaches a specific set of circumstances. Sometimes that restriction is where fittings have been drilled during manufacture, or holes drilled in other components such as tanks. Even an irregular shaped orifice can cause restriction or cavitation under specific conditions.
Without seeing photos or the layout of the fuel system, the problem is difficult to diagnose exactly. Because there are electronics/electrics involved in the fuel system as well, this adds another layer of source potential for the problem.
I would start by trying to determine if the problem is physical fuel flow restriction, or an electronics/electrics problem. Fault finding is a process of gradual elimination, and can be very time-consuming.