Cures shiny with small ‘oil’ marks, but goes matt upon handling

Hello!
So as a result of lockdown boredom and abundance of avocado seeds (a weird a start, but bear with me), I’ve recently been drying these avo nuts out for about two weeks and carving them into rings/O shapes or teardrops. I’ve then been using them as a frame to cure pressed flowers, mosses or dried out little mushrooms, to then use as a pendant. However, I’ve come across a very strange effect though that I can’t work out.

The resin often cures with (very) small oil-y looking patterns on the surface. I don’t mind so much about this, as the surface is still shiny which is what I want, however I’ve tried brushing the surface with a dab of white spirit, soap, or washing up liquid to try and remove the ‘oil’, but when I do this the surface goes matt in some patches. In some cases, the surface will even go matt if I handle it just with my fingers.

I leave the resin to cure for at least 24 hours before touching it, and it’s always hard when I come to it. I also cover it with a glass to stop dust settling on it (or from cats disturbing it…). I measure the resin in syringes (one for the A part, one for the B part), and I reuse them each time (a new one every ten or so uses), washing them with bathroom soap after use. I mix the resin in an empty cleaned out pot, usually a yogurt pot or a milk bottle lid. I also usually reuse this too (e.g. once the leftover resin has cured, I may mix some more a few days later in the same pot, but I always wash it out first to get rid of any oils or dust). I also make sure everything is dry before I use it, as I’ve read that resin reacts badly with water.

I’d HUGELY appreciate it if someone could explain to me what the eff is happening to the surface of the resin, and how I could ensure that it cures shiny, oil-free, and stays that way without going matt! Let me know if any more details are required to get to the bottom of this. Unfortunately it looks like I can’t upload a photo of the problem here ):