How does fusion work on a prism?

[Shockwave]

I rolled a prism to lvl 38 so far.

I have health regen and skill cooldown both to level 10 but nothing happened. (they should fuse)

I have Armor bones and Damage reduction to to 10 and Armor bonus to 8 so not quite to where they should fuse and then I have Skill duration at 1.

I got the first two to 10 as soon as I could and then raised the others but the two 10s never fused even though their roll chance disappeared from the bottom (the fragments).


When does the fusion happen?

[Karagek]

The fusion enters the table for possible rolls around level 5 on both options, however because of the fragments fed to the prism it biases towards the base rolls quite heavily. When you get it down to only having two options left from the unfused table, the final roll should be guaranteed to be a fusion.