Leak between motor and seal plate (new assembly)

My motor died on a whisperflo and so I replaced all parts from the diffuser back to the motor. Worked great for a month or so but now I have water leaking between the motor and the seal plate (hopefully you can see the video here: https://photos.app.goo.gl/uGHXLWD9xtRQhmwg6 - tried replacing gasket on seal plate only after realized it wasn’t from the seal plate itself).

Research suggests it might be the pump seal - would you agree? I used a PS-1000 which is what is listed in the Pentair parts diagram, but have read that perhaps a PS-200 or PS-3867 might be better quality product?

Not sure why the recommended part would have failed so quickly.

Pool is chlorine.

watching some videos ---- I didn’t use silicone when seating the pump seal. Perhaps that’s the issue. I’ve re-assembled a handful of these on different houses and haven’t used silicone before, but maybe that’s my issue.