I have query :
SELECT mean($Parameters) FROM "meter" WHERE "macid" =~ /^$macid$/ AND $timeFilter GROUP BY time($interval), "macid" fill(none)
Do you use
"Description (field)" anywhere completely?
If not, enter
/\(([^)]+)\)/ in the regex field where you're setting up your templating variable and you should only see
field as the templated value.