Affinity Photo - how to "apply layer mask"

[Mic T]

In Affinity Photo, is there an equivalent to Photoshop's "Apply Layer Mask" (in other words, making the layer mask 'permanent' or "baked into" the image)?  I've tried Rasterize but the image gets strange artifacts in it, as though it is being saved to a lower quality.

Thanks in advance.

[Minus44]

Normally, to rasterize the layer might be the way to go. But please share a more detailed description and sample of what’s happening, along with a better idea of the artifacts you’re dealing with.