this happened a number of years ago – I was working at a call center and applying for a salaried position, after interview and selection they let me know that they ultimately decided against going with me because I had been applying for other jobs and didnt want to promote someone only to have them leave.
I looked at them confused and asked how they came to that conclusion – they said that they had saw me updating my resume at work and thought it was in bad taste to search for other jobs while at work. I think I just blinked at them and said “I was updating my resume to include the experience I had received here to ensure my resume was up-to date and accurate to apply for the management position” they then made another excuse about how that was not the perception and perception matters. I counter that they had an incorrect assumption and that was holy on them and 2: a good way to retain an employee who they think maybe leaving is by giving them an incentive to stay: IE paying them more/promoting them, they just countered that they didn't want to reward employees who were leaving and that maybe I would have better luck next time.