Observed Results:
When a trial chamber near lush cave the vines of lushcave spawns inside trial chamber.
Expected Results:: the vines that is shown in below pic should not spawn inside trial chambers 
Steps to Reproduce:
It can be seen below coordinates:
Map seed: -4127325724933606939
Coordinates: -384 ~ -1072

Notes:
As per my guess and knowledge the biome gets mingled up with the structure which could be outcome of this. 
And we could possibly separate the structure and biome which could prevent this happening