OP, I had the Spyder headlights on my Z4M that I sold a while back. The set was not customized so the high beams were the inner lights. It's been a while and my memory isn't fresh on this. But I had similar issues with high beam always on. It turned out the light's internal modules were compatible with European non-xenon pre-face lift models. I had to code with BMW coding tool to such mode to get the lights to be fully operable with the light switch. It took me weeks of head scratching. But after the coding all worked perfectly with the light switch. I was also able to quick flash the inner highbeam with the turn signal stalk.
Check out
https://www.bimmergeeks.net/downloads . They package all the coding tools in a simple download. The tools are in German. So i had to look at a bunch of tutorials. But nothing too difficult to use.