clicking the neutral area on an adjusment layer will target the mask
clicking the neutral area on a pixel layer will target the whole layer
targeting the mask always deletes the mask
targeting the adjustment (icon to the left) deletes an adjustment layer
My guess is that if this changed, it's because previously, deleting the mask on a pixel layer would actually apply the mask (doesn't happen now). That caused so many complaints, and was so incredibly annoying to all of us, that I for one changed my habits and now only use right-click and/or drag to trashcan. I haven't used the Delete key on layers for years.
<edited a few times; took me a bit to figure this out 😉 >