I thought that optimisers and shadow management interfere with each other, that you should use either or.

Optimizers will not run optimally without some sort of "global MPPT scan" or "shadow management".

I had optimizers installed on my strings before the "F150" update.

But due to lack of "global MPPT scan", the power generation stopped once the voltage of the MPPT dropped too much.

Below is a picture with detailed comparison of both firmwares that I already posted here before:

Old firmware had very limited operating range.

And even with optimizers it hit a "wall" below 350V.

There is no "collision" between optimziers and "shadow management" algorithm that I can see in my system.

The only potentially problematic issue is when the inverter does the global scan and the voltage on the string drops. Then the current on the string is increased by the optimizers.

So for instance if your normal Vmp is around 450V and current is 9A, when the MPPT does the scan, the voltage drops to 150V... in that situation current could reach 27A (DC/DC conversion inside the optimizers drops the voltage and increases the current output). I have not seen situation like that in my system so far, but I will keep an eye on it... especially in spring/summer when sun is a bit brighter.

December is probably not the best month to test these things anyway.