Hi and welcome ,
I haven’t used Wled-Jinx yet , i will try to install it
Since you are using e1.31 and matrix then check the below as it has the matrix correct configuration in WLED and the server ( xlights in this case but it should be same ) .
Just test with wled 0.13.0-b4 because this is what i am using and it has the direct setting for a matrix
Report back if this does not fix it and we can test Wled-Jinx