Did you ever resolve this issue?  I have a client that has had the IM_AliasItem clear out every month or so for the last year.  We have had the issue in the 2019 and now 2021 version. We cannot find the cause or solution. I was looking through the activity log and thought it might be period end.  I just ran each module period end in a test company after reestablishing the files content.  Period end on no module impacted the file in the test company.

Did you ever resolve this issue?  I have a client that has had the IM_AliasItem clear out every month or so for the last year.  We have had the issue in the 2019 and now 2021 version. We cannot find the cause or solution. I was looking through the activity log and thought it might be period end.  I just ran each module period end in a test company after reestablishing the files content.  Period end on no module impacted the file in the test company.