Dog suddenly scared of water and food bowls

My dog (6 year old lab/german shepherd mix) is suddenly scared of the food and water bowls he’s had for years. He does eat and drink from them, but he’s very apprehensive when approaching them, he acts a little jittery while eating or drinking, like he’s constantly ready to flee, and he sometimes gets startled by seemingly nothing when eating or drinking. This started a little over a week ago. Everything else is normal, I haven’t noticed any odd behaviour when he’s walking, playing, sleeping, anything really. It’s just the bowls he seems to be scared of. I’ve already put them in a different spot, his bowls used to be next to a trench convector which makes more noise during the cold days so maybe that scared him, but I can’t really think of anything else. He doesn’t wear a collar, so it’s not something clanking against the bowls that scares him. The bowls are reflective stainless steel, and I’ve read stories of dogs being scared of their own reflection in the bowl, but I don’t think it’s that either, because he’s had these bowls for years now. Does anyone have any idea what could cause this?