Night time growling

[Louie and me]

We adopted our dog in June, also a rescue and after an idyllic summer, things changed. As soon as the eveninge began to get darker, Louie would growl and bark and act in a threatening way every time my husband walked into the room. This lasted throughout the winter and ended as soon as it got lighter in the evenings. A behavourist gave us some suggestions such as rattling a can with coins in to distract him, a water spray bottle, etc. but they were only marginally successful. My husband also took over all feeding and exercising in an effort to increase trust since Louie had no problems with me.
In reality, it was only time (about three years) that resolved the situation and the incredible patience of my husband. I'm sure that anyone else would have returned him to the sanctuary. I should mention too that Louie and my husband were the best of buddys during daylight hours throughout this behaviour.
Not sure if this helps but at least you know someone understands the problem.

[shepgirl]

I was wondering if this happenned after the dog got a rabies shot?
My friend had a dog do the exact same thing one day after a rabies shot and found out it was a reaction to the shot. It lasted a couple of months and was over.

[boricuajenny5]

Weird, my 2 year old cockapoo started doing this in the morning! She usually follows me around while i'm getting ready for work, she has done so for the past 2 years, but now all of a sudden she growls the whole time i'm brushing my teeth. She's never had a problem with that before. I try to listen hard to see if maybe she hears something I dont (i'm sure she does) but the dogs in the neighborhood are still pretty quiet when I get up in the morning. My family works the night shift so I try to get her to be quiet by giving her a stern "No" but she tests me and continues to growl but not as loud.

[Blackrose]

Does he have a hard time seeing at night? Are the lights on when you approach him?

I ask, because I was sitting in our living room one evening with my Grandma's Miniature Schnauzer watching TV (no lights on) when my older brother (he's almost twenty) walked into the room with his sweatshirt hood up over his head.
Molly growled, jumped off the chair, and ran over to him barking fully intent on taking down this "intruder". When she got closer she realized it was Jake and she jumped on him and rained him with kisses.

I would feel really apprehensive punishing or startling an already worked up dog, as that can just add fuel to the fire. I'd try to find a different behaviorist that works with positive reinforcement and see what she says about the issue.
Did the behaviorist you contacted earlier give you any idea as to why he was growling?