adder - 9:52 pm on Sep 5, 2013 (gmt 0)
Firstly, Panda has got nothing to do with links. It's based on content and user experience.
To answer your question, yes, I had a client who experienced a similar situation.
Two sections of the website lost nearly 60% of its pre-Panda traffic. The remaining sections lost only 10% or didn't lose anything.
It actually makes sense because if you're not a spammer or scraper, it's likely that only certain parts of your site will be affected.
Firstly, you want to determine if this is indeed a Panda.
In your Analytics, choose a data range long enough to show both the period when you enjoyed high rankings and period when the traffic declined. Print the graph.
Now, check the Google Updates Timeline: [moz.com...]
On your printout, draw a vertical line whenever a Panda update has occurred. Do these lines coincide with a drop in traffic?
Also, you want to make sure you know your niche fluctuations. In other words - are there any seasonal fluctuations in traffic?
If you've confirmed that this is Panda, create an action plan and start working.
A few things to look at: