VICKERS FR2-16-K-12H-/30.00

Pressure-compensated flow regulators are built exactly for that kind of problem. When load pressure shifts during operation, an uncompensated valve lets flow wander, which is what causes that mid-cycle inconsistency you're describing. This one holds a set flow rate regardless of pressure fluctuations upstream or downstream, so your harvester circuit stays stable through the whole work cycle. It handles up to 114 liters per minute at the port level and is rated to 350 bar, so it has plenty of overhead for demanding harvest equipment.