"Non-straightforward case" email from Sheffield - spousal visa

I would go back to the MP and update them.  Tell them you are now told the application is not straight forward and you want to know why - as you haven't had any requests for any additional information, have no convictions or prior overstays, etc.  Hopefully you can get an answer or better yet, they'll just process your visa.

That's what we've done. My partner forwarded the UKVI email on and said basically, "what would have changed in the last 2 working days to take it from no flags and ready to be decided to this?"

As an update, my partner got in touch with the person we've been working with in our MP's office. She didn't seem overly concerned and said that when end of the standard processing time draws near, the email is auto-generated. I haven't heard this before, but that's what she said.

She seemed to think things would still be processed in a relatively timely fashion, not too far out from our current processing times. Given that on Thursday (which was 11 weeks in) she was told by the Home Office that we had no flags, and then on Monday, 2 business days later, we were suddenly too complicated to process on time, I'm hoping that's the case.

Anyway, she did say she'd call again to find out more. Still, it took 2 weeks for her to get a hold of anyone last time, so maybe I'd get a decision before then. I can only hope....

As a further update, I got my "decision made" email today, 3 business days after getting the "non-straightforward" email and still within the standard processing times.

So...I believe it when we were told the "non-straightforward" email got auto-generated toward the end of our processing period.