To answer your questions:
Can you clarify a bit more about what you mean? I am reading your comments as a Mac running Mojave with the SEP client exported from the SEPM with the NON-Catalina build and you are upgrading the MacOS to Catalina? Is that correct in my understanding?
This is correct, we export either the 14.2.5323.2000 or the 14.2.5569.2100 client as a "macOS 10.14 or lower" client to be installed on Mojave machines as the majority of our Mac endpoints are on Mojave or lower. Once installed with the proper KEXT and SEXT rules in place, it functions as expected. However, when upgraded to Catalina, we see the errors asking for permissions to run. Both clients provide the same result after the OS upgrade.
If this is the case you will definitely need to uninstall/reinstall the SEP client. So you need to uninstall the non-Catalina version of the SEP client and then install the Catalina version of the SEP client. This is normal and expected behaviour with SEP 14.2 RU2 and above when exported initially as a non-Catalia SEP client build and installed on Mojave or less. However, if you have the older SEP client 14.2 RU1 MP1 (14.2.4814.1101) and have that installed on Mojave and then take the Mac to Catalina it will continue to work.
Are you saying we need to uninstall the Mojave version (while still on Mojave) and install the Catalina version (still on mojave) before upgrading to Catalina? If so, why would we ever install the 10.14 or lower version on any machine? I do believe we've tested this as well and saw the same results but I'll run it by our other engineers. Seems odd that the older versions would work all the way through but the latest two revisions wont though... We'll test that older version as well and see if we get the same results but don't hold your breath on 14.2RU2 working as we've not seen anything positive on our side.
The latest we've heard from our solutions architect is the following which sounds promising:
My understanding on dev resources is that they are actively working to get a hotfix out for SEP Catalina issues next week.
This was what we received last week so maybe something comes out this week.
I'll update as I hear more.