Security update 2021-007 discards earlier TM file versions?

[LostEmail]

Hi folks, I've just applied the Catalina Security Update 2021-007 and I noticed something unexpected with my Time Machine backups, and I wonder if it's normal behaviour or if I should concerned. I seem only to have backup versions of my files dating from the backup that immediately preceded the Security Update. That is, there are backups dating to January which I can see in the Finder, but if I try to restore a document from (say) my Documents folder using Time Machine, I can only go to the last backup before I applied the Security Update.

I would expect previous versions of documents to be available for all backups that are saved in Time Machine, and that I could, if necessary, restore a document to a version that I was working on and saved a week ago or a month ago. Yet I can't find any files in my Documents, Desktop, Dropbox, or other folders that allow me to roll back before the Security Update. Can anybody reproduce what I've observed and is it normal behaviour? If so, then Time Machine is now really much less useful than it once was, when you could roll back files quite far in the past.
Many thanks!

Edit: formatting

 

[MBAir2010]

All i can type is Catalina did some weird things with my Time Machine back ups as well,
and i had trouble opening some files from other OSXs i could easily perform in Mojave this week.
Just this Sunday i had to remove Catalina after my external drive could not be readable.
perhaps there is a new standard for  to choose security over necessity
and developed software that wont risk opening a file that i know is safe.

there might be third party programs that might open these files deemed unsafe.
i hope to hell not, but who knows anymore?

 

[LostEmail]

Well, Monday I'll check on my work computer if I see the same behaviour there. Perhaps the files are still present, but deemed unsafe as you suggest, but in Time Machine, I don't see that any of my files existed before 26 October (the last backup before I applied the Security Update), even though the folders are there on the disk in Finder. Very strange.

I, too, am pretty unimpressed with Catalina for a number of reasons, but since Mojave is no longer getting security updates, I felt it wise to update my 2012 Mini. I haven't had any real data loss (as far as I know), but things like this on Catalina seem unexpected and worrying.

 

[posguy99]

I did not experience this. Both of my Mac are running Catalina, both have the latest security patch, both have backup history going back into 2020 (I reset TM when I got my 2020 MBP and didn't let it inherit from my previous laptop). In fact my iMac has history going back into 2019.

 

[LostEmail]

Very odd. It turns out that my work computer did the same thing: if I look at previous versions of a file in Time Machine, I can only go back to the date before I applied the security patch. To add to the mystery, the timeline on the right of the screen implies that there are previous versions dating to the age of this computer (and mirroring the dates of the folders I can see on my Time Machine backup disk when I examine it in Finder). However, I cannot select any of those predating the security update in the timeline, or by pressing the "Previous" button in Time Machine.

Oh well, I haven't lost any data (that I know of), and perhaps I brought it on myself by some preference I set somewhere. Just behaviour that I didn't expect.