Sorry, rushed into declaring resolution on the issue.
User Storage SPI documention "Migrating from an Earlier User Federation
SPI" chapter mentions migration from custom User Storage providers, but
my Keycloak servers don't use any custom providers, only default
built-in "LDAP" providers to connect to FreeIPA servers.
I've launched Keycloak 2.5.4 server with completely fresh MySQL
database, but the same issue still persists.
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