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Matrix4 indexes M[i,j] column-first in its vector operator (X' = M00*x + M10*y + ...), while Matrix3 indexes row-first (X' = M00*x + M01*y + ...). Copying the 3x3 block verbatim therefore produced the TRANSPOSE of the intended linear transform, so rotations applied via getWorldMatrix() ran with the wrong sign (arc start/end angles, text rotation, ellipse major axis, etc.). Transpose the 3x3 block in the Matrix3(Matrix4) constructor so that Matrix3 * XYZ applies the same linear map as Matrix4 * XYZ.
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Matrix4 indexes M[i,j] column-first in its vector operator (X' = M00x + M10y + ...), while Matrix3 indexes row-first (X' = M00x + M01y + ...). Copying the 3x3 block verbatim therefore produced the TRANSPOSE of the intended linear transform, so rotations applied via getWorldMatrix() ran with the wrong sign (arc start/end angles, text rotation, ellipse major axis, etc.).
Transpose the 3x3 block in the Matrix3(Matrix4) constructor so that Matrix3 * XYZ applies the same linear map as Matrix4 * XYZ.