I'm using Solve[] to find the solutions to a system of equations, then checking their stability in a Hessian using PositiveDefiniteMatrixQ[] to see how many of these solutions are stable. RegionPlot[] comes in handy to plot the number of stable solutions in terms of the parameters.

An example of the type of plot I want that has worked worked perfectly for another set of equations.

Error Output

{{7 System`ReduceDump`SolveParam[Subscript[\[Kappa], xy0]] + 
   7 System`ReduceDump`SolveParam[Subscript[\[Kappa], 
     xyF]] + (-7 + 
      100 System`ReduceDump`SolveParam[Subscript[\[Kappa], 
        xy0]]^2) System`ReduceDump`X$27813[1] - 
   100 System`ReduceDump`X$27813[1]^3, System`ReduceDump`X$27813[3], 
  System`ReduceDump`X$27813[
   2]}, {{7 System`ReduceDump`SolveParam[Subscript[\[Kappa], xy0]] + 
    7 System`ReduceDump`SolveParam[Subscript[\[Kappa], xyF]] - 
    7 System`ReduceDump`X$27813[1] + 
    100 System`ReduceDump`SolveParam[Subscript[\[Kappa], 
      xy0]]^2 System`ReduceDump`X$27813[1] - 
    100 System`ReduceDump`X$27813[1]^3, 1, 
   System`ReduceDump`X$27813[1]}, {System`ReduceDump`X$27813[3], 1, 
   System`ReduceDump`X$27813[3]}, {System`ReduceDump`X$27813[2], 1, 
   System`ReduceDump`X$27813[2]}}, {}}

It seems to suggest this is an error in the evaluation but I've used ContourPlot[] as alternative to plotting and the output was fine. So I'm unsure whether the Solve[] and PositiveDefiniteMatrixQ[] parts are where the issue is arising - just very messy in comparison to the previous plot which is why I want to try RegionPlot[].

I've also tried setting attributes like MaxRecursion -> 0, PlotPoints and the range of the parameters to small values to limit computational cost but this doesn't change the output. Anyone come across this before?