Hi here,
Sorry for the late answer
Thanks @stephenrpalmer for the meaningful concern and @agabrys for this good clarification!
I removed phrase about deprecation from S2129, it should be updated with next release of SonarJava. Also this ticket is created https://jira.sonarsource.com/browse/SONARJAVA-3031 to ignore BigDecimal(double) in S2129, so that only S2111 reports it.
I think these changes should make experience about this rule cleaner.
Regards,
Lena