Subnautica: 2nd fragment of seaglide not there
The fragments do not always spawn in the same location. There are some locations where certain fragments are guaranteed, but most locations are randomly generated.
For example, the PRAWN and Seamoth fragments inside the Aurora are guaranteed spawns.
The Seaglide fragments can be found all over the Safe Shallows and Kelp Forests, especially near the wrecks or damaged life pods.