I don't know for sure. I can see that the result is the same as Exp@LogGamma[100 - 5/0.015`200]. Gamma[] is negative, so LogGamma[] is complex. Gamma[100 - 5/0.015`] (machine precision) now underflows to 0., with an error message, in V11.3. In V11.2, it automatically is promoted to an arbitrary-precision number that can handle such small numbers. This change in handling underflows is a big change in V11.3. It suggests to me that it might be the reason for the difference in your computation, that they changed how Gamma[] is computed in general to handle the change in machine precision computation.
