Do rottweilers really growl sometimes when happy?

A friend of mine had a rottie and I remembered she loved affection and once when I was petting her whilst she was eating her food, she was growling so I stopped because I thought I was getting on her nerves or that she was going to bite me but then recently I saw a few YouTube videos of people who have rotties and they seem to growl when being petted and not attack their human parents.

Can a growl also mean a sign of affection?

 

Lol, I try not to do it, it's kind of a force of habit sometimes I like to say hello to pets when walking past in the kitchen but I know it's annoying for them so now I try to remember to back off

My wife would definitely not like being showered with affection whilst eating her food, food is something she really must enjoy in peace, otherwise you get the evil eye for the rest of the evening

Thank you though for explaining to me the behaviours of rottweilers. I guess like us humans, they all have different personalities