Evaporation when cover first installed in Fall?

I'm curious if others have experienced water loss (evaporation?) when a cover is installed and it's still relatively warm out?
I'm in SC so pretty hot summers and mild fall weather. Last year I installed our cover in late September to avoid lots of leaves. Our cover is mesh - so rain will pass through. I noticed soon after covering (maybe 3-4 weeks) that the water was way down - probably a foot. I assumed I had a leak and would deal with it in the spring. When we re-opened and refilled I was surprised that it seemed to hold water ok. The drop in water level also leveled out over the winter - although hard to know how much precipitation played into it.
Would covering the pool while it's still warm out force more evaporation that if I covered when it is cooler? It may have just been typical evaporation but it seemed to drop pretty quickly on that first month.

Ten bucks says you have a leak, fairly high up. Water dropped to the leak's level, then stopped.