Until more polling supports this, I'd take it as a likely outlier...at least, in terms of the degree of the shift. Generally, it would not be surprising that Latinos were becoming more opposed to unrestrained immigration...many first generation, blue collar Latino workers are being forced into job competition with this new wave of immigrants. That forces wages downward and makes work harder to find...so its in their interest to oppose the Dems desire for unlimited immigration.
One would think major polling services would be racing to sample Latino's on this issue...because of this represents a genuine trend, it is front page news.