You have an outer voltage to current feedbac loop and an inner current feedback loop. When voltage gets higher current gets higher, the source could sag down if it has a highish output impedance, then voltage gets lower which would set a lower current, then current gets lower, voltage gets higher and so on. Certain loads will induce some oscillations.
To deal with this I'd try to make the voltage to current stage much slower than the current loop so settling is slower but current reacts fast in relation to the sensed voltage, and folows its response. That would behave like an inductive load, current responding slow to the input voltage change. But there's always some input condition where it gets tricky to stabilize. Dealing and testing with it is easier in a simulator as you can generate any source you like, you can test different input conditions and find a feedback configuration that works nice. Look my design of the CV/CC load where I did so and I came up with a reasonable fast and stable config, I've only run simulations on the final circuit, the one I've build was a previous version.
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