LVM commands return "Failed to create regex device filter" error.

Issue

• LVM commands return "Failed to create regex device filter" error.

lvscan
   Invalid filter pattern "a/dev/mTST.*|".
   Failed to create regex device filter

pvscan
   Invalid filter pattern "a/dev/mTST.*|".
   Failed to create regex device filter

The *lvm* filter in */etc/lvm/lvm.conf* file is 

filter = [ "a/dev/mTST.*|" "a|/dev/sd5.*|", "a|/dev/xs.*|", 
"a|/dev/md.*|", "a|/dev/ld.*|", "r|.*|" ]