Now getting

Notice 0: Finished DEF file: /project/openlane/user_proj_example/runs/user_proj_example/tmp/placement/replace.def
Warning: could not find power special net
Design Stats
--------------------------------
total instances        398959
multi row instances         0
fixed instances        135872
nets                   263165
design area          10173980.2 u^2
fixed area           176439.2 u^2
movable area         3873665.2 u^2
utilization                39 %
utilization padded         65 %
rows                     1286
row height                2.7 u

Warning: detailed placement failed on _417365_
Warning: detailed placement failed on _219169_
Warning: detailed placement failed on _219098_
Warning: detailed placement failed on _218128_
Warning: detailed placement failed on _417025_
Warning: detailed placement failed on _219362_

Thousands of these detailed placement warning Project and runs checked in at https://github.com/miscellaneousbits/caravel_sha3_256_crypto_miner.git branch miner project user_proj_example. Any ideas why?