Mottled new leaves on Phal. Surf Song

[BrassCat]

Have a Phal Surf Song from Hausermann’s that has developed strange mottling mostly on the underside of the new leaves. I’ve had the plant for about 18 months now and it’s been growing well.

I have slow release fertilizer in the pot and it’s potted in mostly coco chips, some moss bark and perlite as well. Though I know there is no way to tell, I’m curious if you think this is a virus or some sort of nutritional deficiency? I planted this one in the coco as a sort of experiment and don’t have other plants in that medium, wondering if maybe the coco might cause this? Also thinking it looks like mosaic virus, but have not encountered that before. Also included a picture of the blooms, I think all surf songs have that color breaking but unsure. Thanks!