It can always happen that an arrow shows an unusual flight behavior. A typical behavior is when the arrow makes unnaturally large changes in direction. Another indication is when the arrow rotates in flight and does not fly evenly. Any type of irregularity should be investigated.
Basically, I was able to determine three reasons for deviating flight behavior.
This can be remedied by pulling the foil cone upwards at the point where the imbalance exists.
Over time it can happen that the fixation of the foil cone loosens. This is e.g. This is always the case, for example, when the arrow penetrates the target up to the silicone tube. In this way, the fixation is pushed up bit by bit. At some point, the upper fixation has partially migrated over the shaft and the foil cone is no longer tight. This is easy to control. Always take a look at the darts from above. If the black dot of the carbon shows up clearly and distinctly on the shaft within the foil cones, the fixation is sufficient. If it is no longer visible or only partially visible, the fixation should be renewed.
There are different types of damage that negatively affect the flight characteristics of the arrow. Are the silicone hoses z. B. damaged by hits, it is possible that the film cone gets an imbalance that can no longer be eliminated by plucking. In this case, the silicone hoses should be replaced. The foil cone itself can be damaged. Either by hitting other darts or by wear and tear. Wear and tear is inevitable over time through use. This can be seen in frayed edges or discoloration of the foil cone. In both cases, the foil cone should be replaced immediately.
After a foil cone has been readjusted or repaired, this arrow should be tried out directly and individually. This is the only way to determine without a doubt whether the work was worth it. If in doubt, further adjustments can be made immediately after the first shot. I don't think it's very helpful to simply mix it in with the other arrows without checking it.