What are the cloud-like blobs in the Martian southern hemisphere?
From the Nature article, the authors propose two alternative explanations:

We used photometric measurements to explore two possible scenarios and investigate their nature.

For particles reflecting solar radiation, clouds of CO2-ice or H2O-ice particles with an effective radius of 0.1 micrometres are favoured over dust.

Alternatively, the plume could arise from auroral emission, of a brightness more than 1,000 times that of the Earth’s aurora, over a region with a strong magnetic anomaly where aurorae have previously been detected


Importantly, both explanations defy our current understanding of Mars’ upper atmosphere.

I think, they are the most trustworthy interpretations that one can get.
Please note that, even if the data are from 2012, the paper is published in 2015, therefore the interpretation is not outdated.