I have received email that my visa application Deferred – complex

I have applied for my visa on 21 of jan in Qatar and submitted the biometric at that date and today i have received this email, im a bit worried, can you clarify for me
Unfortunately, the processing of your application has not been straightforward and we will be unable to decide your application within our customer service targets. We are continuing to work on your application and aim to make a decision as soon as possible.

We will write to you again if there is any change to this. Please do not attend the Visa Application Centre until you have been advised that your application has been decided and that your passport is ready for collection.

Given the complex rules, this may be a common letter.

Or (unlikely?), you are a victim of a remnant of a discontinued policy?