Observation BPM notification disappears after 4 weeks

Summary:

We recently rolled out learning observations for managers. Process is we assign the observation to the colleague and the manager will receive a BPM notification in their worklisst. However it seems to disappear after roughly 28 days so the only way they can access it is to click into the worklist so the BPM pop up appears and they need to search the name of the colleague

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Is there a way to prevent it from disappearing from the bell icon alerts

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