I’ve seen some other threads about this already, but the suggestions there didn’t seem to help so I guess I’m making a new thread, sorry about that 
Basically I get spammed with perl warnings after every update, sometimes even intersecting each other somehow. I think this started happening after I changed some locale settings from KDE’s settings app, and I haven’t been able to undo whatever caused it. The language seems permanently stuck to "", despite my attempts to set it to anything else.
The errors in question:
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = "",
LC_ALL = (unset),
LC_CTYPE = (unset),
LC_NUMERIC = "en_GB.UTF-8",
LC_COLLATE = (unset),
LC_TIME = "en_GB.UTF-8",
LC_MESSAGES = (unset),
LC_MONETARY = "en_150.UTF-8",
LC_ADDRESS = "ro_RO.UTF-8",
LC_IDENTIFICATION = "en_GB.UTF-8",
LC_MEASUREMENT = "en_CA.UTF-8",
LC_PAPER = "en_GB.UTF-8",
LC_TELEPHONE = "ro_RO.UTF-8",
LC_NAME = "en_GB.UTF-8",
LANG = "en_GB.UTF-8"
are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_GB.UTF-8").