BigDecimal has nothing to do with the issue. There is no race conditional. The code is textbook example how to use (cheap) unsafe publishing with no locks/CAS

BigDecimal has nothing to do with the issue. There is no race conditional. The code is textbook example how to use (cheap) unsafe publishing with no locks/CAS -- assign to local variable and 'return' the variable value (not a class member one). There is no global cache, it's per BigDecimal instance. As for 'this bug', yes JVM concurrency bugs are serious by definition.