According to the Path of Exile Wiki, Unrelenting is a Juggernaut Ascendancy passive skill that increases the damage inflicted per Endurance Charge and decreases Elemental Damage when Endurance Charge is at a maximum. With the advent of Version 2.4.0, Endurance Charges have a 25 percent chance to become maxed out on any given charge, which some players may find problematic.
Specifically, Unrelenting has been nerfed from its previous form in 2.3.0, where every time an Endurance Charge was gained, the character would receive a maximum charge every time.
Path of Exile gamers who play Hardcore Melee have an appreciation for consistency in the results they get while defending their builds from attackers. What it comes down to, ultimately, is what was Grinding Gears Games’ intent Unrelenting, by making this change. Path of Exile items tend to change value from time to time, in response to, or to stimulate different behaviors from the player population, and these behaviors go hand-in-hand with their attitudes and beliefs. For some, the goal of Unrelenting is to confer maximum Endurance Charge, which means that the Juggernaut’s EC would always be at full capacity unless Discharge or Immortal Call is used. However, players who assemble a coalition of Juggernauts can easily exploit this mechanic. By cycling their Endurance Charges, they create a perpetual state of Unrelenting, and have an enormous advantage over a single, lone build.
The problem with the current iteration of Unrelenting lies in the momentary synergistic invulnerable effect that occurs in conjunction with Immortal Call. As the saying goes, “power corrupts, and absolute power corrupts absolutely.” Players were making Immortal Call their staple, and had this spell on active status on a permanent basis.
One possible solution to this imbalance of power is to make the use of Immortal Call costly. For example, Grinding Gear Games could initiate a CD counter upon expiration of Immortal Call. Although this may be too much of a nerf in the long run, GGG can titrate the counter to maintain the delicate balance of difficulty and playability. By implementing a tradeoff, players would have to be more judicious in their approach.
Another thing GGG could look into is decrease the chances that a Juggernaut build has to max out its Endurance Charge with each subsequent charge. Whether this necessitates the creation and implementation new different PoE items to facilitate or negate this change, the goal would be the same: to manipulate the amount of elemental damage inflicted each time an Endurance Charge is encountered. Putting an arbitrary cap on the number of Endurance Charges available for a specific time interval, kill ratio, or other parameter may also warrant strong consideration.
Juggernaut was born as a traditional Melee character, and having a strong Melee defense is the cornerstone to playing this class. However, with Unrelenting coupled with Immortal Call, the Juggernaut is particularly unique in its ability to absorb physical attacks. It would be disingenuous to assume that Grinding Gear Games intended for its player base to abuse IC, especially considering how Path of Exile has come to enjoy such longevity as a result of variety, rather than monotony and predictability.