This sort of FSC is due to masking artefacts caused by the mask generated by the FSC calculation algorithm. You would get the same artefact in RELION if you provided a mask that was too tight. RELION provides a warning message when you get that, however cryosparc does not.
I have previously asked about this: Artefactual FSC in homo_refine
A solution can be to provide a mask manually or to drop the threshold for the dynamic masking. I have gone as low as 0.05. A good idea would be to look at your map.mrc file as well as the mask files (both mask_refine and mask_fsc) and see if the masks are cutting your protein density.
I believe my problem is disordered protein density at the surface of my molecule. Could this be an issue for you also?