Wrinkles usually happen when the local water table gets higher than the pool water level. That will cause the liner to start to float up and it can sometimes shift position while floating, before going back into place (or almost into place) when the water table goes down. If that is the issue here, the only way to avoid it is to keep the water level in the pool extremely high when the water table level is high.
There are some other possible causes, but they are all rather less likely.