Crane Card Not Functioning Properly
I played a Crane card to improve one of my cities from level 3 to 4 by paying 3 coin cards. In that same turn, I collected another 4 coin cards by using the commodity monopoly card and by trading. Consequently, I was not allowed to improve that city to level 5, while the Crane card should have remained active.
The Crane card does not remain active for your entire turn. The Crane can be used for only one single city improvement advancement. It's like a single wildcard commodity that can only be applied once.