The Wiki says that pointed dripstone should grow to a maximum length of 7, and should grow a stalagmite on a solid block 11 below.

In the current version, the stalactite continues growing to 8 blocks (if the stalagmite underneath is broken) and then stops generating stalagmites even if there is room on an unobstructed solid block underneath it.

At length 1-7, the stalagmite is generated correctly on the block underneath.