Yes there was always something about the people monty used to do it to, particularly one man we used to meet he always stood still necer spoke and monty woild do his ime aggressive dont come near bark with the o.m.g ime a chicken backing off routine
i learnt ages after monty decided he was a little strange that someone knew him in the village as being questioned for having children in his home
(say no more) one man he used to behave like this with was someone we met several times and one time i looked back and saw him hit his dog across the back with a stick, after these experiences i never worried too much maybe its a good thing at how amazing dogs are sensing these sort of people, does make you feel very safe. All i used to do was call his name and usually he came to me still looking back barking
or i used to go up to him and put him on the lead I wouldnt worry about it just trust your dogs instinct and walk away.