Upgrading Jungle Items from Recommended List
It appears that if you have a jungle item enchantment in your recommended list the enchantment is 'paired' with a specific upgrade to the machete meaning that you can't click and buy the recommended enchantment if you buy a different upgrade.
I ran into this issue with Nocturne, whose recommended jungle item enchantment is the Devourer however, in the preferred items list, it defaults specifically to the 'Devourer' built of of a 'Poacher'. As I had built a 'Skirmisher' I was puzzled as to why I couldn't upgrade my Jungle item (the recommended devourer was marked as being unpurchaseable). I did eventually determine how to make the upgrade but it seemed unintuitive thanks to the crossed circle indicating an illegal buy in my recommended list.
I'd recommend removing the enchantment upgrades from the recommended list so that players don't get confused by seeing an 'unpurchaseable' enchantment if they happen to buy the non-recommended machete upgrade. This would make purchasing the Jungle Enchantment the the same as purchasing an enchantment for your boots.
Alternatively you could 'uncouple' the enchantments from any specific machete upgrade but I imagine that solution would be a fair bit more difficult to implement.