Just had another quick look at this schematic shows another more serious prob with the way the current sense amp U3 is controlling the pass transitor via U2 .This is not going to be stable since these two amps alone without any other poles will cause a close to a 180 phase shift (each contributing nearly 90 each in the way they are configured).
I tried simulating a similar setup and it was totally unstable in cc mode most of the time spice wouldnt even sim it .if your CC stays stable under most load then i'm a monkeys uncle.
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/xsmiley.gif.pagespeed.ic.R8GFI-pF6f.png)
The way to do it would be to let U3 control Q2 directly .(so the anode of D9 goes to the base of Q2 .And you put a 3K ish resistor on the output of U2 ,enabling U3 to directly pull Q2 base drive down.
Alternative would be to make U3 very low fixed gain( flat response so no phase shift)
but I prefer the former way.
If I feel like it this week ,I will post the quick spice analysis sometime .
Regards
p.s Correction ,when I said both opamps contribute 90 deg ,I was mistaken, the second opamp U2 only behaves like a follower to U3's input so contributes no gain or phase shift .I was to sloppy with my quick generic sim ,,but that still looks iffy loop . It's got no phase margin and it's teetering right on the brink and starts oscillating under slight changes .
Perhaps I or someone will do a more thourough sim this weekend.