No, it's nothing to do with code - it's data.
I took the Croft Brown airspace from here
(Tim Newport-Peace format) and adapted it for Spine. It needed adapting because CB set all danger areas to TYPE=PROHIBITED, which I changed back to TYPE=DANGER. Otherwise there would be solid red splodges all over the map.
As for D216, I see it appears twice with different top alt and slightly different coordinates in different parts of the file:
Croft Brown original
# Dated 20 Mar 03 ENR 5-1-3-11
CIRCLE RADIUS=2.00 CENTRE=N520453 W0024806
CIRCLE RADIUS=2.00 CENTRE=N520449 W0024759
My changes just involved changing the PROHIBITED to DANGER. I didn't notice the duplication.
I don't have an up to date chart (retired from gliding), so perhaps you could post what the chart actually says this should be (with the correct coordinates.