It seems faketime prevents date's --utc option from working - under
faketime date gives the same output with or without --utc (NZDT is my
local timezone):

$ date
Fri 17 Jan 2025 14:44:50 NZDT
$ date --utc
Fri 17 Jan 2025 01:44:50 UTC
$ faketime -f '1980-12-08 00:00:00' date
Mon 08 Dec 1980 00:00:00 NZDT
$ faketime -f '1980-12-08 00:00:00' date --utc
Mon 08 Dec 1980 00:00:00 NZDT

I would expect the last command to report:

Sun 07 Dec 1980 11:00:00 UTC

I've filed at the default priority as I'm not sure what's going on and
so don't know what the full impact of this is.

Cheers,
    Olly

How odd.  This appears to be the same as upstream ticket #444

I investigated a bit myself and I don't have an explanation.  I
haven't got out the source code for gnulib, which (from the upstream
ticket) seems like the next step.  I did some other experiments and
the behaviour is certainly odd.  I notice that your time
specification, `1980-12-08 00:00:00`, doesn't state the timezone; that
probably isn't helping.

I propose to leave the severity at normal for now.  As a workaround,
`TZ=UTC date` may help (but may change the interpretation of your time
specification).

Thanks,
Ian.
(not the maintainer, just trying to fix faketime for the moment)