MySQL mentioned in your question on StackOverflow doesn't have the
TIMESTAMP WITH TIME ZONE data type. It means your application uses different data types with different database systems.
JDBC drivers by default return TIMESTAMP values as java.sql.Timestamp (R2DBC returns them as java.time.LocalDateTime).
Both JDBC and R2DBC drivers return TIMESTAMP WITH TIME ZONE values as java.time.OffsetDateTime.
spring-data-commons is able to convert LocalDateTime to Instant, but it doesn't have a built-in converter from OffsetDateTime to Instant.