Comment 7 for bug 1958260

This is a problem for raspberry pi and has been reported as bugs with docker (missing ip_tables module) and other packages around the internet. It seems this has been a problem for a few releases. Raspberry pi images have this package installed by default and it is part of the -server meta package. I believe this is because the initrd and kernel are, at least initially, external in /boot/firmware. I am not sure the logic of copymods, but it does not seem that it accounts for the system being updated after boot.
If additional non-default module packages like -extras get installed, they are installed in the tmpfs because copymods has overlayed a tmpfs after boot. If the modules packages include hooks to copy into initrd, those modules will work, but not all module packages include these hooks, nor should they if the additional modules are not required before root is mounted.
Would it not be more appropriate for the copymods union to overlay the actual disk? I guess I understand why this too would be difficult, but overlaying a tmpfs with apt et al. unaware seems like it is going to persist problems like this unless copymods includes some shutdown task to write the modules in the tmpfs back to disk/flash on shutdown.