This obviously was not highlighted when I copied and pasted it or am I missing something? (ref post 59)
Yes you are missing something
when you copy and paste on this forum it doesn't copy the formatting.
But we know that io540 didn't go and add the underlining after you post because if he edited his post after someone posted another post, then pprune tells us that he did so and the time that the last edit was made. For example we can see that you edited your post 59.
It doesn't show any editing of io540's post so we know that the underlining WA always there and you didn't notice it or failed tho take it into account.