drop_metadata seems to apply to all outputs

[d-p-simpson]

Hi,
I am still quite new to liquidsoap, so very likely this might be an easy one for somebody, however, much search doesn't seem to find anyone asking this exact question. But, it's probably like that I've not fully grasped how something works.

I have a playlist source ("s"), an emergency file source("emergency") (from examples I've seen), and multiple outputs (different bitrates etc).
It all worked well enough, until I tried to configure two outputs to drop the metadata. The method I attempted to do this was have a second variable ("swometa") and use the drop_metadata on that:

# excerpt
# "n" gets list of files
# s (here's the radio)
s = playlist.list(n, mode="randomize")

#silence detection
s = blank.skip(max_blank=2., s)

#crossfade
s = crossfade(fade_out=3., fade_in=3., duration=5., s)

#uniform sound
#s = normalize(s)
#s = nrj(s)
#s = nrj(normalize(s))

#buffering to prevent stutters
s = buffer.adaptative(fallible=true,s)

# A live source
#live = input.harbor("live",port=8080,password="hackme")

#fallback
emergency = single("/mnt/music/Music/2010/#old/519762_Ocean_Drive_Boulevard_Original_Mix.mp3")
s = fallback(track_sensitive=false, [s, emergency])

#s without metadata
swometa = s
swometa = drop_metadata(swometa)

#so, now we have "s" with metadata, and "swometa" that shouldn't have metadata
#outputs
#ogg flac without metadata
output.icecast(%ogg(%flac),  host = "localhost", port = 80, password = "", mount = "ogg.flac", icy_metadata = "false", swometa)
#an mp3 output with metadata
output.shoutcast(%mp3(stereo=true, stereo_mode="stereo", bitrate=320, internal_quality=0), host = "localhost", port = 8000, password = "", s)
#an opus output without metadata
output.icecast(%ogg(%opus, channels=2, bitrate=320), host = "localhost", port = 80, password = "", mount = "320.opus", icy_metadata = "false", swometa)

There's more outputs than this, but to get to my problem, these outputs using "swometa" didn't have metadata, which is what I wanted, but I discovered that the "s" outputs, didn't either.
I did a fair amount of playing around and couldn't seem to make it behave how I wanted.
I am thinking that my understanding of how liquidsoap pipeline or script works is simply wrong, and the "swometa = s" and "swometa = drop_metadata(swometa)" did not do what I had imagined. (You can also see, I tried something with icy_metadata to false to see if that work do something).

I did try looking for functions that would create a duplicate of the same input, couldn't really see anything. I did also try have it doing the playlist mechanism twice, but my concern there is that having it doing two inputs would mean they will eventually get out of sync, I'd prefer to have the same single input source, so to speak.

Many thanks in advance for reading this long problem, and probably simple overlooked, or misunderstood situation!

*** UPDATE ***
I have noticed that in actual fact, after about 20 minutes, the metadata intermittently starts working on "s", and still is stripped out of "swometa" - and then it seems to stop again... weird.