you're at max pressure the seals can handle, time to play with the other settings. Running it in rebound XC setting should be stiffer and maybe hold weight better. All the way open will bottom the fork out sooner and fork travel will be slower. 30% sag in a 120 fork is fine.
https://manitoumtb.com/wp-content/up...etup-Guide.pdf
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Rule #10 // It never gets easier, you just go faster.