After starting Mathematica and loading a file with Manipulate and ContourPlot3D function I get the message: ContourPlot3D::valuef: B2[x,y,z,0.05,0.05,0.015,Br] must be a numerical function. >>. Evaluate Notebook here after gives the intended functionalty without any error message. Close all and reload the file gives again an error. Close file and reload gives no error message. What is happening here?

Structure: - initialisation variables - Defintion of a vector function B2[x, y, z, a, b, c, Br_] := .......... Manipulate[ {Show@MapThread[ContourPlot3D[#1, {x, -0.1, 0.1}, {y, -0.1, 0.1}, {z, 0, 0.1},Contours -> Range[-Brange, Brange, Brange 0.1], BoundaryStyle -> Directive[#2, Thick], Background -> Black,Boxed -> False,RegionFunction -> (! (#1 [GreaterSlantEqual] -0.0001 && #2 <= 0.0001 && #3 [GreaterSlantEqual] 0) && ! (#3 <=0) && ! (#3 > Alfa) &), ContourStyle -> Directive[Opacity[0.8], Specularity[White, 10]], ImageSize -> {400, 400}, ColorFunction -> Function[{x, y, z, f}, Hue[ 2 f]], PlotPoints -> 20 (Hi + 1), MaxRecursion -> 0, Mesh -> False, Lighting -> "Neutral"] &, {B2[x, y, z, a, b, c, Br] {sx, sy, sz}, {Red, Yellow, Green}}]}, Row[{Control[{{a, 0.05, "a"}, 0.001, 0.1, 0.001, ImageSize -> Small}], Control[{{b, 0.05, "b"}, 0.001, 0.1, 0.001, ImageSize -> Small}], Control[{{c, 0.015, "c"}, 0.001 , 0.02, 0.002, ImageSize -> Small}]}, Spacer[10]], Row[{Control[{{Alfa, 0.1, "Z"}, 0.001 , 0.1, 0.005,ImageSize -> Small}], Spacer[20], Control[{{Brange, 0.5, "L"}, 0.05 , 1, 0.05, ImageSize -> Small}], Spacer[10], Control[{{sx, 1}, {0, 1}}], Spacer[10], Control[{{sy, 1}, {0, 1}}], Spacer[10], Control[{{sz, 1}, {0, 1}}], Spacer[10], Control[{{Hi, 0}, {0, 1}}]}]]! Sample output included

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