I found a thread on this forum with this problem, on searching on having the same problem - 10 speed chain getting jammed between middle and small rings on this 9/10 speed chainset.
Spa Cycles was surprised, but really helpful, when I raised the issue. They sent me a set of 0.45mm chainset spacers, which I used to push the middle ring inboard a touch. On initial test rides (loaded shifting slowly on friction shifter while going up fairly steep hill) I couldn't persuade the chain to jam in either gap.
It is odd that this issue is not routinely designed out of chainsets. But its a good value chainset otherwise and I'm happy with the fix.
As searching for the solution got me to the other thread (which I can't find now...) figure this might be a good place to share the information.
