While patching 19.3 GRID_HOME with July2019 RU patch 19.4 I got this error:
[root@fzppon06vs1n bin]# export PATCH_LOCATION=/u01/oracle/RU_PATCHES/29708769
[root@fzppon06vs1n bin]# $GRID_HOME/OPatch/opatchauto apply $PATCH_LOCATION -oh $GRID_HOME
OPatchauto session is initiated at Mon Sep 9 11:00:57 2019
OPATCHAUTO-72083: Performing bootstrap operations failed.
OPATCHAUTO-72083: The bootstrap execution failed because OPATCHAUTO-72146: Failed to load patch
OPATCHAUTO-72146: Failed while collecting patch information for patch /u01/oracle/RU_PATCHES/29708769.
OPATCHAUTO-72146: Check the log for more information..
OPATCHAUTO-72083: Fix the reported problem and re-run opatchauto.
OPatchauto session completed at Mon Sep 9 11:01:02 2019
Time taken to complete the session 0 minute, 5 seconds
opatchauto bootstrapping failed with error code 255.