Ok, So I have spent the last 4 hours trying to debug this thing and I just can't seem to figure out what's wrong. When I set up the LM431 on it own on a breadboard it works fine and outputs -2.5v but when I connect it to the PCB the output changes again.
The original design was made by Louis over at Scullcom Hobby Electronics (He makes fantastic videos, check his channel out). I will add the PDF of his schematic to this post so that you can see it. The only differences I have in mine from his is that I opted not to have a trigger input, otherwise my schematic is (or should be) identical to his. I watched through his series of videos covering this design, particularly the one where he calibrates the load. In that video, he starts by calibrating the 4.096v reference (R31 on my schematic, RV5 on his), then the voltage readout (R5 on my schematic and RV2 on his) then the current null calibration (R29 on mine, RV3 on his), and lastly the current draw calibration (R26 on mine, RV4 on his). I tried to calibrate my load in the exact same order but, every time I change R29 then the 4.096v reference goes down to around 3.1v, and I can't get it back to 4.096v unless I change R29. Also, the -2.5v goes down to around -0.6v when I do this. In addition to that my voltage readout slowly goes out as the voltage increases, so at 5v it is perfectly accurate but at 30v it is 0.7v higher which is a big problem and no matter how much I adjust R5, nothing changes. Lastly, the current calibration doesn't seem to work on my board. Once I try to change the current null calibration, it throws off the current calibration and even if I don't touch the current null calibration, at low currents (500mA - 100mA) the readout on my load is very off. If I set it to draw 100mA it will only draw 70mA but the load will display that it is drawing 120mA, and when I adjust R26 the actual current draw only goes up by about 7mA and the reported current draw doesn't change.
At this point I really don't know what to do

, I have gone through both my schematic and His schematic to look for differences and I just can't seem to find any. I was hoping that you guys would be able to take a look and see if there is something that I'm missing or doing wrong. I would really appreciate it!
Thanks so much!
FYI: The file titled "DC Load" is my version and the other one is His.
Louis's Video: