Enticing's affect is "instant" and working as far as I know...if you have save game where its not working, please submit a ticket and we'll take a look

https://esupport.stardock.com/index.php?/Tickets/Submit

It's a one-time effect that instantly flips all planets and starbases within your influence when you unlock it. If you select it when there isn't anything to flip, it'll do nothing and waste the trait, so choosing a good time is important.

I do recall wondering whether it was a one-off or permanent thing when I first read the description.

Yes this trait requires a bit of timing to be most effective.  In my last game, I used it to turn the tables on a faction that had just declared war on me  

As others have said, timing is critical to use of this trait. If done while you have coverage of Minors, starbases and majors planets you can easily double  your empire with it. I save it till I have four things to acquire.

Thanks for the explanations. Fixing the UI text to make that clear would be very helpful.

The way I read it, it seemed like something to go for when you finally decide to try an Influence victory and want it to roll through quickly. But now that y'all make me think about it, that sounds like a fat bag of exploitability.