Sé que habrán or Sé que habrá?

On this timestamp of a song with ed sheeran and J Blavin, he says Sé que habrán momentos de sufrimiento (I know there will be moments of suffering), my question is why isn't it Sé que habrá momentos de sufrimiento, as I thought Sé que habrán momentos de sufrimiento would mean = I know "they will have" be moments of suffering

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https://youtu.be/bqtMJ391poA?t=26

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https://preview.redd.it/nxlv453p69691.png?width=547&format=png&auto=webp&s=dabd11d295636f54a6019da9590b016e12f3d52f

https://preview.redd.it/gfbotr1q69691.png?width=538&format=png&auto=webp&s=22882988e7706427f447a632ffde737a333b47d5