High sap content with low padding content will almost always do that. It's why those paspds are so cheap and prone to failure, because you get what you pay for.
I don't normally use booster pads though. Long ago I realized it's better to combine the cost of a diaper and the booster pad, and just get a better diaper at that same price. You'll end up with every bit the same absorbency or more, and will also have a better functioning diaper that is WAY less likely to leak.
For the few times a booster does make sense, the absolute best functioning with lowest cost possible is a baby diaper. Because of their economy of scale. I tear off the side tapes (it's incredibly easy, just hold it at the base of the tape and pull up. They come off very easy this way). When it gets saturated enough it will overflow into your adult diaper. Or you can change it out with another one to greatly extend the wear life of your adult diaper.