If you look up our Lubuntu 22.04 issue tracker you’ll see that was added in 24-Dece-2021 by myself (my primary box sits on the development release, though I didn’t notice it until I rebooted which I do only fortnightly).
The issue was last detected using the 2022-01-22 daily of jammy with Lubuntu, having been resolved after that, before finally dropping off our issue tracker on 24-March-2022 for Lubuntu 22.04 LTS on the thread I provided earlier.
It wasn’t a problem per se, just a security difference with prior releases; with the behavior reverted to what was used in prior releases (ie. it explores/peeks-inside other partitions like it did before)
The problem didn’t exist in 22.04 media; nor 22.04.1 media; only very old alpha ISOs. Lubuntu media is identical in this regard to main Ubuntu, or all other flavors as grub rules are common for all.
In QA-testing the dualboot installs were performed with other releases of Lubuntu, other GNU/Linux distributions, plus with windows 10. I stopped experiencing that issue in the alpha stage of jammy (22.04); others may have tested other OSes in dual boot beyond what I mention here, and my own testing includes up to 4 OSes on the same machine.
Myself, I don’t believe it’s a problem, however as the thread you provided was answered by a Lubuntu member @ArrayBolt3, he may respond here as well, or you can ask him questions if you wish.