I'll be keeping an eye on that when mine arrives from Big Chief Studios. With something like this do you go back to the reseller you bought it from or back to HT directly?
Looks like an issue with the disappearing ink in the fabric pen they used for marking the stitch lines. Hopefully it's contained to just a few batches and is not widespread, because yikes...
Edit: Searching online it appears you can first try removing it with water, or otherwise white vinegar or hydrogen peroxide should work. But obviously test it in a small area first.
I've tried cleaning one of the spots with a wet wipe and it seems to take it off quite easily. It's still there but a lot fainter. Might try some proper cleaning stuff before I send back