The tiny perforated layers almost look as though the printer was skipping some of the layers (especially since you have areas where the layers look nice… then you get to areas where you have all the gaps/perforations in some layers.)
You updated your firmware to make sure the printer knows you are running the SL head?
Also, you updated Cura so it knows you have an SL head (it’s not still using the default .5mm nozzle size in the software config?) It will normally (by default) “skip”) printing areas where it thinks the detail needed is thinner than the nozzle can provide.
I have had issues on some of my prints where it was skipping layers. In my case I could fix it by using the “print thin layers” option in Cura (you might have to go into Preferences to enable the feature because on my Cura-LulzBot Edition install it wasn’t in the custom settings until I turned it on.)
BUT… I was able to find the areas of my parts where I was having problems, turned on the “layer” view in Cura (after slicing … if auto-slicing isn’t enabled you wont be able to go into layer view until you click the “prepare” button to get Cura to generate the slicer path) then use the layer view controls in Cura to step through layer-by-layer and watch how the print head moves … especially in the layers where I had problems. To my surprise… it wasn’t a printer problem, it was a slicing problem. The printer wasn’t laying down filament because the Cura g-code path was telling it to skip those layers (“print thin layers” fixed that). But Cura skipped the layers because it thought I was trying to print detail with my 0.5mm nozzle which required things that were thinner than .5mm. This is why I asked if both Cura and the printer firmware are updated to know you are using a .25mm nozzle.
I’m not sure if any of this will help, but this is the stuff I can think of checking. Good luck!