Hi Niaduz,
Can you please refer the following 2 SAP Notes and check whether it helps you:
2255402 - Precalculation: One or more Precalculation Server randomly cannot report status and hangs for some time while getting the status. After some time, the status is incorrectly reported as
OFFLINE and after the instance completes the processing of the current workbook, the instance may give the correct status.-Backend part
2253929 - Precalculation: One or more Precalculation Server randomly cannot report status and
hangs for some time while getting the status. After some time, the status is incorrectly reported as
OFFLINE and after the instance completes the processing of the current workbook, the instance may
give the correct status.- Frontend part
And, can you please apply latest Patch Level of SAP GUI for Windows 7.40 (Patch Level 6) and latest Patch Level for BI 7.0 ADDON FOR SAP GUI 7.40 (Patch Level 401) and check whether it helps you.
Also, please refer the following SAP Note:
147519 - Maintenance strategy / deadlines for SAP GUI
Thanks & Regards,
Sapna