Posting Error - Post locked

Update: I ended up deleting everything in Post (except for saying it was reposted due to errors) and reposting and it saved OK with correct URLs...weird.

Created a Post in Knife Maker's Discussion called Knife Tracker App. I have two files that are too big to upload as attachments, so I created a URL link for them. After saving, the actual URL has been 'changed' (missing a backslash after http:/) and now I can't save the post after I edit and correct the links. Error says spam-like or invalid context. I even deleted both links and post still won't save. Post now has two invalid links and generate an error when you click on them. As a retired web developer this is not friendly posting composition behavior.