What PSU do you have? Ignore my previous comments about the driver’s ability to handle 3s, that was based mostly on the bad data. Based on the new data you’re just seeing normal behavior for a QX9920 I think. I now see no problem.
If it suddenly cut off without dimming I’d assume that it’s the MCU’s LVP stopping the output rather than limitations of the buck circuit. I could be wrong though.
ImA4Wheelr and I aren’t just asking about the sense voltage for curiosity, you should check that again. With such a low sense voltage I think precision adjustments (eg precision low-value resistors) may get expensive. Instead I’d look at the link I provided in post #26. If you follow that thread you’ll end up over here (#106) where Pavithra_uk explains how to calculate the gain on your op-amp. Adjusting the gain may be the easy and cheap way to change your set current.
In fact, I just glanced at the pics in reply #1 here and I see the 153 and 202 resistors (15000ohm and 2000ohm). Looks like the gain is set exactly the way Pavithra_uk described for the SRK over there. Reducing the gain as described in some of those posts will push your sense voltage even lower, giving a higher set current with the same sense resistor (R010). You can pickup a large 0805 component assortment (I assume that the 153 and 202 resistors are 2mm long, right? That’s 0805.) from Sure Electronics for <$9, I’d recommend that.