"G exceeds the film's range due to reciprocity adjustments" is a message that can be shown on the exposure section in ExpoDev under some situations starting with ExpoDev version 1.1.1. This message is ExpoDev letting you know that the chosen exposure, when corrected for reciprocity, is outside of the range of your chosen film's test data. This can happen even when the metering section tells you that the scene's SBR is within the film's range since these reciprocity adjustments are only applied once an exposure time has been chosen.
ExpoDev corrects for a film's reciprocity failure by applying a set of adjustments to compensate. ExpoDev will adjust both the exposure time and the Average G (which affects development time) to compensate for the effects of reciprocity failure. How much adjustment for each of these depends on the exposure time chosen. In some cases the necessary Average G adjustment may cause the result to exceed the range of your film's test data.
When this situation occurs you will have to change the exposure time to a faster speed to lessen the amount of correction needed. Note that in some cases this may mean that you have to eliminate reciprocity compensation altogether in order to pull the exposure back into range. In these cases you will have to change the metering and/or the chosen film to bring the exposure back into the range of what your film test data can handle.