I was hired a few years ago as a Senior Engineer and was excited to accept the offer, the pay was much better than my previous job so I accepted the new offer without negotiating salary nor did I think there was room for one. A few months later I was part of the hiring committee that hired another Engineer (within the same dept but for a different team, but we work closely together). After the new Engineer started working with us, it became apparent that their programming skill was not really that great beyond attempts to just make something work, which oftentimes is a brute-force approach. Many times they come to me for troubleshooting their own code issues even for solutions that would only require a simple Google search.
After a while, the new Engineer was asked to report to me indirectly so that I sort of "mentor" them, so I set up regular meetings with them to go over tasks and do some pair programming. After a while, I stopped having these meetings because it was pretty much useless and a waste of both our times. At this point, the dept's upper management decided to move her to my team. While all this was happening, I became aware that they are paid more than me, and I'm certain they did not negotiate their salary as well. This disparity was initially brought up by the manager we both report to and was acknowledged by me as a concern. They also made it known to me that when I was hired, I was presented with the salary lower bound for the position (with the expectation of me possibly negotiating), while the new Engineer was presented with the upper bound (which meant that they could not have negotiated a higher pay even if they tried to).
During our subsequent "mandatory" salary increase for the next fiscal year, everyone got the standard % increase, and I got 2x that in an attempt to close the gap, with a view of eventually surpassing them with subsequent 2x increases, this was my understanding. A new salary increase was recently announced and to my surprise, we both got the same % increase, which is different from my previous understanding. Going at this same increase rate, the gap will begin to widen. I lead way more projects within the dept and do more collaboration with outside depts.
I plan on bringing up this discussion ASAP with the manager but really unsure of what my approach should be given that there was never a written agreement. Or even if it is worth bringing it up at all.
I'm located in the US.
I'll appreciate some perspective on this issue.