SwiftPages in UITabViewController turn blank randomly

[cesare-montresor]

I'm have an issue that happens randomly with SwiftPages, I use it inside a UITabViewController in 2 different tabs. By doing a little bit of debug I've noticed that the problem is actually that a 2nd SwiftPages it's allocated and placed on top of the previous one :(

Normal situation:

Bug appear:

I've tried already by load it programmatically or via IB, no difference. Do you have any clue about what could cause it ? Thanks