During a warm or emergency start, CICS recreates the tables from the resource definitions stored in the system log and global catalog.
If you have named a different list in the GRPLIST operand, or if you have added new groups to it after the last system initialization, CICS does not install the groups in the new list during a warm or emergency restart, because CICS does not refer to the list.
If you usually use START=AUTO at CICS initialization, using the INSTALL command is your standard way of making resource definitions available to CICS. You use a list to define your system only when you need to do an initial or cold start. You can ensure that your list is up to date by adding to it each group installed using the INSTALL command.