This is either a bug or an undocumented change to Necromancers. The skill Blastbones and all its morphs are now spawning in a new location. On PC/NA live server, the blastbone skeleton spawns in front of the caster as seen in the video below. On PTS servers, the blastbone skeleton spawns to the side, and a little behind the caster, also seen in the video below.https://youtu.be/oOERNiVxuBg
This is a small adjustment but it almost completely ruins the flow of Necromancers in PvE.
Currently, on live servers, if you are in melee range with a target and cast blastbones, there is enough time to use 2 other skills (2 Global Cooldowns of 1 second each, or GCD) before the blastbones explodes and you can cast blastbones again. A very seamless flow of skill order/class identity.
On PTS, if you are in melee range with a target and cast blastbones, there is still enough time to use 2 other skills (2 GCDs) before the blastbones explodes, AND an additional ~ 0.5 seconds (One half of a GCD). This additional time puts the player into a limbo where the blastbones is about to explode, so they cannot yet recast the skill, and there isn't enough time to do an entire singular GCD skill.
It may seem very minor from watching the examples in the video. But in group PvE content where the flow of the fight can be heavily altered for the worse by a singular cast of an incorrect skill. As well as the sheer amount of skills cast during a boss fight in any trial or dungeon, this "limbo" time quickly adds up and results in a very unenjoyable experience for the class.