python3-module-custodia-0.6.0-alt2.noarch owns the same files in /usr/bin/ as python-module-custodia-0.6.0-alt1, so it shoudl declare a Conflict Otherwise apt-get dist-upgrade fails, because it doesn't know that it should remove the old package.
My apologies. The fix is coming up.
custodia-0.6.0-alt3 -> sisyphus: Fri May 24 2019 Stanislav Levin <slev@altlinux> 0.6.0-alt3 - Fixed update (closes: #36781).