Hi,
I forgot to mention that in the latest release the time for decay threshold has been changed to 1 year. You may want to change that limit as specified in the release notes of version 11.2:
The default value of the time threshold for radioactive decays of ions - above which these decays are ignored - has been changed, from 10^27 ns (i.e. about twice the age of the universe) to 1 year. For applications where radioactive decays of ions do play an important role, it is recommended to increase the default time threshold of these decays to a very high value, e.g. 1.0e+60 years. This can be done in either one of the following three ways:
Via UI command, e.g. /process/had/rdm/thresholdForVeryLongDecayTime 1.0e+60 year, (command to be used after /run/initialization);
Via C++ interface, e.g. G4HadronicParameters::Instance()->SetTimeThresholdForRadioactiveDecay( 1.0e+60*CLHEP::year ) (to be placed in the main program before run initialization);
Via the second parameter of the constructor of the class G4RadioactiveDecay (for analogue mode only) or G4Radioactivation (for both analogue or biased mode), e.g. G4RadioactiveDecay( "RadioactiveDecay", 1.0e+60*CLHEP::year ) or G4Radioactivation( "Radioactivation", 1.0e+60*CLHEP::year ) (this is for custom physics lists, before run initialization).