I'm about to buy this used Giant TCR (year?) road bike, but I noticed it has a raised mark on one side of the fork. The bike shop knows nothing about it and it seems structurally fine. May it look like a fixed fork? Could be an acceptable defect? It seems to be happening in a transition between aluminum and carbon fiber.
To me it looks like a very shoddy job of quality control initially, or a poor repair that has been painted to match the bike. I'd suggest comparing the paint on both sides of the fork to see if there's a difference in colour, gloss, or texture. The decal on top might also not be original.
Noone can tell you categortically it is safe, or if it will last for years. There are services that do non-destructive testing and scanning of items like frames, but they're more about looking for voids and delaminations.
Your bike shop's warranty should give some indication of how much they really trust the bike. If they are only offering the minimum warranty period in your country, vs offering a 2 or 5 year or "lifetime" warranty on the frame.
Note Giant bikes mostly had "lifetime" frame warranties on anything that wasn't a downhill bike.
In the end, you could buy and fit a new replacement fork, to reduce the risk.
Talk it out with the shop, and see what they say. If used bikes are selling well, they won't move. If they want to get the bike sold, they might offer to install a new fork for free, if you buy a fork through them. Negotiate.
I don't want to be the naysayer but the fork exhibiting the same flaw in both sides in the same place and being the type of construction it is, I would very strongly advise you to consider replacing it, especially as a new carbon fork of better quality, from a recognised brand name, can be obtained for 100-200£, depending on the quality you want. If "any fork will do", you can spend as little as £30 on a cheap steel fork.
The carbon legs are bonded to an aluminium crown and the point the paint is cracking is the top of the carbon, which is sleeved over the aluminium section. As the fork has done some work, the bonding between the two is now allowing some movement which has cracked the paint and implies that the bond between the two sections is not as secure as it once was.
Newer carbon forks tend to be fully carbon, which eliminates this weak spot. Even where the steerer is alloy on a newer fork, the fork crown is generally now carbon.
The likelihood is that yours won't fail unless you crash or bump something fairly hard, but it is still a weak point and they don't last forever. It is the least pleasant part of the bike to fail, debatably!
Ultimately it's your choice. I'm advocating replacement.