Help! Washing line marked custom t-shirt

[FairfaxAikman]

Brought in the washing and found a beloved custom t-shirt I had made for DS has a stripe mark across the back.

I don't think the mark was there before (DH hung the load out) but think it unlikely as it runs where the fabric was against the line. There was other washing on the line and it's all unmarked.

Can anyone shed any light? And is it possible to save the shirt?

It looks like it's been bleached! 😱

Looks possibly like the dye has dispersed, maybe try washing it again and see if it evens out a bit?

It looks bleached but I can't see how it can be - it was against the line which is kept outside, so no change to come into contact with bleach

Wash it again and see what it looks like?

Has someone wiped the clothes line with a cloth that has been in contact with bleach?

That stringy streak of a liney bastard!

Phew. Put it on a quick 15 min run W cycle and it APPEARS to have gone. But will wait and see what it looks like when dry

It looks like how I've ruined clothes before, used the bleachy utility cloth to wipe the line rather than the soapy kitchen one then pegged washing out.
If its bleached don't think it can be fixed but I'd throw it back in the machine and see what happens anyway.