You're not the only one. It appears also the Governor of the province, Juan Pablo Placido, is saying he has no details as to why the presidential visit was suspended. This was non-reason posted in today's internet edition of El Siglo. (Spanish Language)
One could only speculate as to why at this time. I think it is directly or indirectly related to presidential safety concerns in regards to adverse public response to the fuel price increase.
Regards, PJT