Training slash missing

We consolidated 3 of our websites into one new one. We have an old website , https://DrSophiaYin.com that we have pointing to (via HTaccess) to this page on the new website: https://cattledogpublishing.com/dr-sophia-profile-history/

Here’s the problem. If I try to set up a redirect for the blog posts, When someone clicks on an old link , for example https://DrSophiaYin.com/blog/entry/video-tag/target-training/ , they end up with this URL. https://cattledogpublishing.com/dr-sophia-profile-historyblog/entry/video-tag/target-training/

Note the trailing slash is missing from between /dr-sophia-profile-history and blog/. It’s configured correctly (I think) in the HTasccess file as it has the trailing slash in the code, and in the redirect. What am I doing wrong?

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