I see them now – it looks like your iron might be a bit too hot, but it’s hard to tell in the pictures. I don’t normally see the woven fabric get shiny like that. (What I see doesn’t look like a problem though.) The fabric shouldn’t melt at all, just the TPU. Lowering the temperature a bit will also reduce the chance of it melting through to the bottom of the floor – just be sure to test some scraps whenever you change the temperature.