Package on Arch Linux has incorrect signature

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The package 'lmms', which can be retrieved using the package manager pacman in the Linux distribution Arch Linux, appears to have a faulty signature. As follows is the given error:

error: lmms: signature from "Lukas Fleischer <lfleischer@lfos.de>" is invalid
:: File /var/cache/pacman/pkg/lmms-1.1.3-4-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]


As I am a little hesitant to install packages with invalid signatures (don't blame me), I will go ahead and install it from source. However, someone might want to look into this.
Should you not contact pacman, who makes the package ?
Justist wrote:The package 'lmms', : in the Linux distribution Arch Linux, appears to have a faulty signature.
Thanks for your report, but as gps said, this is beyond our grps control.
Please do inform the pack-man.

Besides that since you are new in our forum;
Welcome Justist ! Here are all our important links:
http://lmms.io/forum/viewtopic.php?f=1&t=4740
-And a few rules for Avatars, signatures, posting and using the right sub-forum :)
Is your system clock set correctly?

https://wiki.archlinux.org/index.php/Pa ... leshooting