Well, you solved an issue, but not the one in this question, ahahhahahaha.
To wrap it up:
There were some little (non)zeros in the matrix and writing Symmetric() solved the issue.
Now numeric results go as expected.
However it solved it without using MKL.
Without MKL:
02 | -0.37499999999999944 | 0.0 | -0.18749999999999972
04 | -0.9098524898764083 | -0.26742624493820444 | -0.22746312246910208
08 | -1.9485400435360116 | -0.25967188841490085 | -0.24356750544200145
16 | -4.017274038426099 | -0.25859174936126095 | -0.2510796274016312
32 | -8.154573454879735 | -0.2585812135283522 | -0.2548304204649917
With MKL and MKLSparse:
02 | -0.37499999999999944 | 0.0 | -0.18749999999999972
04 | -0.8321067811865448 | -0.22855339059327268 | -0.2080266952966362
08 | -0.7678727796362532 | 0.016058500387572894 | -0.09598409745453165
16 | -0.09950923658373387 | 0.08354544288156492 | -0.006219327286483367
32 | -7.511857594535956e222 | -4.694910996584972e221 | -2.347455498292486e221
and while I know the first results are now right, the last ones are wrong