When modifying fixed-end anchors in PLAXIS 2D 2010 in an already defined (and calculated) model, the meshing + regeneration process will reset these fixed-end anchors’ properties (the equivalent length and the angle) to the original property values.
This has been fixed since PLAXIS 2D 2011.00
Workaround: in order to update the fixed-end anchors with the correct properties, remove the fixed-end anchor and apply a new one with the correct properties prior to generating the mesh. Note that you will have to check all settings in all phases for these fixed-end anchors.