Yes, I see it a lot in my life. We see a whitish line at the top of the hoof. It means the hoof has absorbed more moisture than it can handle. It will go away when the hoof dries out, but prolonged excess moisture can cause damage, and any damage to a hoof toe takes about 12 months to disappear. Maintain the right amount of hoof moisture at all times is tricky. My farrier recommended no turnout when the grass is wet. I check the grass by walking through it and seeing whether my footwear gets damp. Lush pastures or those with areas of tall grass like around manure take the longest to dry. The farrier also said no more than 20 minutes at a time, twice a day after the dew dries off. It isn’t just rain and snow that is the problem, it is heavy dew, and we had that in VA last year. Also, urine in stalls is a problem, so stalls should be heavily bedded and cleaned after each elimination. We use hoof sealants also.