When created plannig area time series in /sapapo/msdp_admin , some key figures (manually uploaded data) has disappeared from the planning books.
original date was. 01.01.2019 - 31.01.2023 , and the modified was 01.12.2021 - 31.12.2023.
Is it the standard way that date disappeared? What is the root cause?
Any ways to avoid such except backing up the Parea?
Not really clear what you mean here - if you change the initialzation time range of a planning area - of course the data outside the new time horizon is lost since the time buckets are removed in the livecache.
Keeping data is typically a matter of xreating a backup process in APO. If you do the admin of a Planning Area there some functions to create a Backup Infocube based on your POS (chararcteristics) and PA structure (keyfigure + time horizon). Create a transformatuion from the PA DataSource to this infocube + DTP etc. and then you can run a backup and restire if needed. The latter can be done using report /SAPAPO/RTSINPUT_CUBE.