Volcano and Weapon swapping with shapeshifting

Noticed I've been having trouble casting Volcano from weapon swap. It's not coming out sometimes when I just click and don't hold. It works fine form human form, without swapping. if I cast it, and have my wand out, then short click, it will come out with a short cast. However, if I'm in a shapeshifted form(any), then short click to cast from weapon swap, it will do the cast animation, but the volcano will not come out. Tested bonestorm(another channel spell) and other spell skills, and they work fine from swap with just a single click. This bug makes my build feel incredibly bad, and I didn't understand it until a few people pointed out the bugs with other weapon swaps from other skills, such as walking calamity.

I have the same issue and it's easily reproducible. Shapeshift > Cast Volcano > Observe

It also may be based on cast/skill speed, because I just got some more skill speed and it's working better?

like there is some minimum cast time necessary, and it is lowered by speed stats.

Edit: However, if I lower the cast speed of volcano with considered casting support, for example, it still functions correctly with my better skill speed. Very strange.