I’m actually having a simular issue. When I schedule out posts, they get cross-posted to tumblr early (generally at the time when the previous post is scheduled– so if i have a post today, the one that gets cross-posted to tumblr is tomorrow’s post, etc) and when it posts to tumblr, I get an error on my dash:
Crossposting to Tumblr failed. Remote service said:
Response code: 401
Response message: Not Authorized
Couple problems with this:
a) I don’t do anything with the API key and future posts still get posted, albeit early.
b) when I go to check on my tumblr API keys, they’re all fine and not blocked or anything.