It seems that the new code creates proof of stake blocks, but they fork away from the main chain as they're never accepted by the other nodes. At least this happened to me.
The UTXOs I am staking with have a balance between 600 and 10000 SLM. If this problem doesn't affect any other people, Is it possible that the new staking algorithm favours really big stakers?
Possibly the problem already existed with iguanodon1's code. I later tried it with the old 0.5.0 (pre-iguanodon) code and staking went well without problems. As I tried it two times with each version, I think this is really a problem of the new code.
Cheers
Graham