Flip Coin and Summon Spirit Sphere

[Frogboy]

i have a question regarding these two skills...

i've made a gunslinger and have the flip coin skill. i use it and gather my coins up. after some time they go away (probably about 3 minutes of time passes since i gathered them). the skill description says they cannot be lost unless on relog or death and neither of those happens in that amount of time.

so my question is this: is the description wrong, and does summoning spirit spheres work in the same manner or is the skill not working correctly?