I think I might be doing something wrong? Several times now in the browser version I've bought what's said to be permanent upgrades, but when I'm reborn the only ones that stick are the one for the rebirth stone and the auto-farming. It's been a bit of a pain getting to over level 20, only to have the skill I was trying to nab not be permanent like I thought it was. Do you know what I might be doing wrong?
It's hard to say exactly, but just in case let me list the farmhand perks that are permanent:
Destiny - Autofarm - Autoskill: Golden Harvest - Empowered Hunger - Autoskill: Midnight Oil
Any other skill is not considered permanent - are any of the above the ones you were purchasing but then didn't retain?