I’m also having this issue. I had this downloaded for quite a while before noticing in Marketplace that an update was available. No matter what I did the update status didn’t change. Foolishly I deleted the pack off my xbox and tried to redownload it getting the above situation described in the bug. Unfortunately none of my worlds are playable now as they indicate: “There was a problem loading pack. Restarting your game or redownloading the pack might solve the issue.”
This morning I updated my xbox to 26.10, making sure my download cache was cleared, and was successfully able to download the texture pack.