You have to mount the bottom right emitter opposite on that Noctigon if you’re running series vs parallel, even Richard could make that kind of mistake. If he thought they were going to be in series he would have put the positive to the right, when it needs to be to the left, double check that bottom right emitter with the branding oriented properly on the 32mm Noctigon. See if the bond wires are on the left. That’s proper parallel orientation.
A picture of that mcpcb would tell us a lot, if the bridges are radiating outward, that’s parallel. If they’re in a radial or horizontal, then it’s bridged for series. Double checking those and that single emitter will probably find the issue.
Here’s a 32mm Noctigon with parallel, the bond wires are to the left on the bottom right emitter.
If it’s wired for series that bottom bridge wont be there, probably not the top one either. Series wont’ need those bridges populated.
Edit: Neither bridge set is for Series, they’re both for parallel. And the series + and - pads are in-line with the 3 emitters, one on one end of the string, the other on the other end. and that middle emitter gets put on the opposite way.
If in Series, the - pad is the one at the top of this second picture, closer to the word Noctigon, the + pad is next to the 3 Oz designation for the trace pour weight.