When uploading a file using the T-code 7KEX, the period sequence displays improperly.
The order of the periods is altered.

As an illustration, the period is shown as follows in the excel file:
1 2 3 4 5 6 7 8 9 10 11 12

Following upload, the time frame became as follows:
12 11 10 9 8 7 6 5 4 3 2 1

However, the proper period order is 1 2 3 4 5 6 7 8 9 10 11 12.

The incorrect file description is the root cause of the issue.

Please remove the file description assignment in T-code KP34PC.
Run the RKCDPREO report after that, then remove the file description
(After deletion, RKCDPREO no longer lists the file description.)
Then, in T-code:KP34PC, create the file description as usual.
Afterward, it ought should function.