After removing the IP core from the EDK design (by using the option => delete instance and all of its connections) the error message about the constraints related to the removed core is displayed:
'ERROR:ConstraintSystem:58 - Constraint <TIMESPEC TS_verticies_to_FFS = FROM
FFS(*logi3D*u_render_list/v*_regs*) TO FFS 20 ns;>
[hp069ac_2d3d_fmc.ucf(107)]: FFS '*logi3D*u_render_list/v*_regs*' does not
match any design objects.'