And yes, you should do something about it, but don't overreact. If it has progressed slowly, that requires a small adjustment... faster = bigger adjustment.
Up the N proportionof fertilzer while minimizing impact on other nutes as best you can. Simple paling will turn green again,but any necrotic damage will not heal. Look for a change in the trend, not necessarily overnight fix... if it stops getting worse you know you did the right thing. if it reverses, same thing. But, make sure to keep an eye on it so that you don't go too far the other way.
There is a goldielocks zone for each nutrient. Interrelationships (mulder's chart) and pH can impact what that exactly is at any one moment of time and why it may be different from one grower to the next.
if you want more guaranteed consistency, go soilless/hydro.