Dye sublimation distortion after pressing

Are you trying to do sublimation on black material? Or is your design black? If it's the design that is black it could be just where the print head is clogging or not printing correctly. Maybe some air in your lines that is causing the ink not to come out completely.

Or maybe some moisture in the material, or too much humidity in the paper, or maybe the paper was exposed to sunlight. I don't know. Could also be a cold spot on your press.

If you printed a different design and pressed would the error be in the same spot? It alomost looks like it is being caused by whatever you are using underneath the garmet on your platen not providing even heat.

Just a thought

I am sublimating on a white garment so the purple you see is indeed ink and this has happened to other sublimated jobs. Currently I am using a felt pad and then underneath the felt a 1/2" thick foam pad. Every once in awhile the foam pad gets super saturated from all the gassing and I noticed that the pattern on the shirt is on the foam pad. I am assuming that this mark is being transferred thru the foam pad onto the shirt however Im hesitant to confirm that idea only because in order from bottom to top is 1/2" thick foam pad, Felt pad, kraft paper and then garment. So I wasnt sure if the pattern that im actually seeing on the foam is transferring all the way thru.

Try cleaning your pad with rubbing alcohol. I'm thinking there is something in your pileup there that is wrinkling under pressure. Either the fabric is wrinkled, or the foam, or the pad.

Your layers should be the bottom foam pad, then a piece of copy paper the size of your print (this protects the pad from ink), then if printing over seams the other pad - though felt pads are for ceramics and this is most likely the source of the printing error, then the fabric face up and the transfer face down, then the kraft paper or copy paper the size of your transfer.

Are you "dressing" your press with the shirt or just laying both layers of fabric down on top of each other?