Slimes not Spawning in Slime Chunks

My friends and I started out a new server on 1.13. Upon loading the world, We attempted to build a slime farm below Y40 at a known slime chunk in the world. After several weeks of play time, we have only discovered a single slime. We tried other slime chunks in the world and no dice. I attempted to achieve slime spawns on a single player world recreating the same area on the same seed and was able to get multiple in a few minutes.
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Is the seed in question. The slime chunk, in particular, I am trying to analyze is centered around 37 -618.
I appreciate any and all help