Hi, have seen this problem reported before and bug reports filed, but don’t know if the bug was ever fixed or wether my case is the same. Running Calc (LO 4.4.6.3) on Linux 64 bit, and my comments are randomly disappearing. At first I thought perhaps I’d accidentally deleted them but not this time. Saved the workbook yesterday with several comments and comment indicator enabled. Opened it today and ALL comments have vanished - not just the indicators, the comments are gone as well. Any thoughts or help much appreciated.
Can’t help, but I had the same problem in V. 4.4.2.2 in Windows 8.1 and 10. Just upgraded to V. 5.0.3.2 and now I can’t even enter a comment. The box appears and I can’t type in it! I should have stayed with Office
I hear you and you have my sympathies. Thought I’d got past this somehow as comments on my main spreadsheet have been stable for a few weeks now, but just opened it up and a random selection of comments are gone. This is a deal breaker for me unless it can be fixed - will have to go back to Excel 
Just happened to me the same problem, my comments have just disappeared on one sheet, all other sheets are ok, no comment loss. (ods file type, its possible that the file was created originally with openoffice).
I wonder if it is possible to retrieve it?
Win7Home Version: 4.1.6.2 Build ID: 40ff705089295be5be0aae9b15123f687c05b0
I’ve found that since installing version 5.2.6.2 comments that have been individually entered reappear when a spreadsheet is re-opened but vanish if copied from another cell or sheet.