No, you appear to have a legit bug. The bug presents in JDK7 but fixed in JDK8. Your values are correctly representable as BigDecimals, and should behave correctly, but don’t.
Tracing through the source code of BigDecimal, on line 2585, this.precision() is 1, and this.scale is -2147483647. this.precision() - this.scale therefore overflows, and the following overflow is not handled correctly.
This bug has been fixed in JDK8 by doing the subtraction in long arithmetic.