Convalescence used on weapon swap does not switch weapon, but can still be used

If Convalescence is equiped on second weapon slot, and you use it with first weapon equiped, the following (bugs I think) happen:

a) Skill uses the skil duration of weapon set 1, not 2
b) Skill does make the caracter weapon swap, yet still gets used
c) Skill Can Be Used, even though Weapon set 1 does not have enough spirit to reserve it

I.E I have 100/100 spirit reserved for Set 1. 30/100 for Set 2 (only Convalescence reserved.) and I can still use convalesence as if it was reserved for set 1.

How I imagine this should work, is that my character should first swap to the second weapon set, THEN activate the skill.