OKay... when login rewards became a thing, I logged in every day for a few weeks, and as each line of rewards filled I'd do a claim all, and chuck the crate and its rewards into the legacy hold to deal with later. This eventually became too much like work, so I took a break. Came back for the new update and out of curiosity decided to look in one of the crates to see if there was anything useful to my current toon. I noticed 2 things.
1. The crates in the Legacy hold are all marked "Bound" rather than "Bound to Legacy"
2. If I move a crate to my inventory it still shows "bound" but I can't open it, or put it back in legacy hold. I can however put it in the cargo hold. I can take it out and put back in the cargo hold all I want, but it still wont open.
Edit:
Apparently logging out, and back in allows me to open crates retrieved from the Legacy Hold. So it's not the end of the world, but it is still a bit annoying that the crate cant be put back in the legacy hold.