Crowns lost after crash
I hereby pretend to state the problem I encountered.
I purchased the palisade upgrade and began with its construction, however, the game became unresponsive and I was forced to close it and re-open it.
When I started the game again, I noticed the palisade upgrade did not remain, so I attempted to purchase it again but I realised the crowns had been deducted.
Basically I lost the crowns for said upgrade without being able to benefit from the upgrade itself.