Same issue today.After using the "clear_array_for_shrink" userscript array not stopped so ;
-I manually shutdown the server,
-removed the disk which one is cleared by the script
-restart server
-array not started automatically
-in main menu opsions Parity is valid didn't appeared
-then went to tools -new config
-Preserve current assignments click to all
-checked I want to do this
-then in main menu Parity is valid appeared
-then checked Parity is valid and start array
-everything is normal now
-I bought 20 tb hdd and replace 3 3tb hdd one by one with this method and everything is correctly working now.
-Thanks to spaceinvader