could be just me, but 6 months seems like a long time to run a set of tires. I probably get about 3k miles per set, so go through 3 sets or so a year. I’m not sure how much mileage you are getting. Those cracks don’t look good. Looks like dry rot. The rubber is breaking down. This usually occurs because of exposure. weather, sunlight, chemicals or oils in the road. Have you been riding in bad weather? Are you roads particularly oily? Is the bike kept indoors and away from windows? Whether they are worn or not, I’d replace these asap. They are at the end of life.
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How and where is that tyre stored? It looks like its starting to rot?
EDIT: Great minds @russell.r.sage 
I usually run my tyres for a year - I would not expect them to look like that after 6 months.
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I get various degrees of cracking on GP5000s. I don’t think it’s a safety issue. I’ve never seen one de-laminate or anything like that. The cracks tend to look worse in digital pics that are enlarged.
Ditto, and think I might have ran the 5000TL’s longer and they never looked like that. The 5000S TR’s though seem to randomly stop holding air at circa 70psi. Like the weekend before last when I was standing stationary for 10 mins with the bike unloaded and then after 5mins chatting (again stationary and unloaded) pst a tiny hole blows and sealant splurts out until its lost a bit of pressure. Its the same when I pump it up in the flat, fine at circa 60psi but if I pump to circa 70 psi it’ll randomly blow after 30mins or so. I replaced a previous 5000S TR which looked in excellent condition but was doing this too often. I’m sure it would have been fine just pumping to 60psi but it got annoying 
I stored the bike inside at room temperature. There is no direct sunlight in the room. There was no elements except for the sun when riding and around 90 degrees heat. I figured I rode about 2,500 miles over the six months. I am starting to think these tires are indeed defective.
The sealant inside was completely dry, but I do not even want to try. Before I installed the inner tube, this tyre was losing air very fast through the cracks. From my past experience using Stan’s sealant, it was not able to seal even small sidewall leaks like that.
I saw a post on this forum or possibly another and the person got a free replacement out of Continental for cracking.
I have 2 years on my front 5000TL and six months on my rear tire and I don’t have nearly that much cracking on the front - hardly any. (I don’t rotate tires.)