We too have had this problem twice in a year. Sealand sent us an updated seal and spring cartridge at no charge, the first time at 6 months . I've replaced the seal again since then at about 11 months. I'm not sure you can rotate the seal as someone suggested, as there is an index tab in the plastic base and a notch that the seal fits into. Someone else recommended a silicone lubricant. This is against manufacturers recommendation and the petroleum content will likely further damage the seal. I've read where someone used non-stick cooking spray, but I've seen little help from this.
Everything so far has been what I consider a temporary fix. I suspect this will be a persistent maintenance problem.