The router gives priority to fixing hold violations by detouring through longer paths. However, this adds more restrictions if the violations are inside the CONTAIN_ROUTING static Pblocks. There might not be enough solution space for detouring inside the static Pblock that includes a CONTAIN_ROUTING requirement. Therefore, Xilinx strongly recommends having a good post-place timing summary for such logic. For techniques to reduce unique control sets, see this link in the Versal ACAP System Integration and Validation Methodology Guide (UG1388).