He who is dpb said on Tue, 24 Oct 2017 07:54:31 -0500:

It isn't that unusual that there is just a whiff of the odorant not
fully burnt when the burner first ignites.

I was going to mention that some people are super sensitive who can
supposedly "smell" when the gas is low, simply because the oderant gets
concentrated due to its properties when your gas supply is low.

That only works for those with external tanks though, and not for those
with a permanent connection to the gas line.

The odor isn't gas; the test "sniffer" they use is quite sensitive and
if it didn't indicate the presence of gas you can be comfortable there
isn't a leak...

Exactly my point. The gas guy is trained to sniff stuff out. If he doesn't
sniff stuff, then at that point, there's no leak. If the homeowner *still*
thinks there is a leak, then all the normal options apply.

1. The possibility exists that the owner was wrong
2. The possibility exists that the gas guy was wrong

The simplest solution, logically, is to call the gas company again and get
a *different* guy.

They can't all be the nephew of the owner's brother...