We should probably remove liblsan and libtsan too (same SONAMEs in GTS 9 and in system gcc), though they don't cause any issues.
Related: bz1729402
I verified there was Transaction check error(s) present when trying to install gcc-toolset-9-libubsan-devel and gcc-toolset-9-libasan-devel in a case libasan5 and libubsan was installed for gcc-toolset-9-gcc-9.1.1-1.el8 and installation is successful for gcc-toolset-9-gcc-9.1.1-2.2.el8.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2019:3440