[arch-general] udev complaint and USB malfunction

[set at nmset.info]

This message appears in /var/log/errors.log (using syslog-ng)  (don't know 
since when): 

systemd-udevd[424]: /usr/lib/udev/rules.d/99-indi_auxiliary.rules:5 Invalid 
value "/bin/sh -c 'test -f /sys/module/usbcore/parameters/usbfs_memory_mb && 
test $(cat /sys/module/usbcore/parameters/usbfs_memory_mb) -lt 256 && echo 256 
> /sys/module/usbcore/parameters/usbfs_memory_mb'" for RUN (char 76: invalid 
substitution type), ignoring, but please fix it.

I don't have a clue about an appropriate fix, apart from deleting 99-
indi_auxiliary.rules, and don't know how valid it would be to delete this file.

I'm having this strange USB behaviour on 2 machines : 

Plugging a USB stick may not trigger the 'New device' popup in KDE, while 
lsblk does list the USB stick. The latter may be connected directly to the 
machine, or via extension cable or a USB hub. It works half of the time as 
expected.

An this one on one recent host :

A USB 3 hub (tried 2 hubs) may not always list its devices, with these errors  
on resume from a *long* suspend, or on reboot :

Jul 31 12:24:22 localhost.localdomain kernel: usb 5-3: device descriptor read/
64, error -71
Jul 31 12:24:22 localhost.localdomain kernel: usb 5-3: device descriptor read/
64, error -71
Jul 31 12:24:22 localhost.localdomain systemd-udevd[408]: /usr/lib/udev/
rules.d/99-indi_auxiliary.rules:5 Invalid value "/bin/sh -c 'test -f /sys/
module/usbcore/parameters/usbfs_memory_mb && test $(cat /sys/module/usbcore/
parameters/usbfs_memory_mb) -lt 256 && echo 256 > /sys/module/usbcore/
parameters/usbfs_memory_mb'" for RUN (char 76: invalid substitution type), 
ignoring.
Jul 31 12:24:22 localhost.localdomain kernel: usb 5-3: device descriptor read/
64, error -71
Jul 31 12:24:22 localhost.localdomain kernel: usb 5-3: device descriptor read/
64, error -71
Jul 31 12:24:23 localhost.localdomain kernel: usb 5-3: device not accepting 
address 5, error -71
Jul 31 12:24:24 localhost.localdomain kernel: usb 5-3: device not accepting 
address 6, error -71
Jul 31 12:24:24 localhost.localdomain kernel: usb usb5-port3: unable to 
enumerate USB device

I can't know if all these are related. I am requesting help in search of an 
easy fix.

Thanks and regards.