Tova

Since you mentioned it does it hot or cold: worth also noting whether it does it after the car has been sitting for days versus after a short stop.

A fault that only shows up on the first start of the day points at something that settles or dries out. A fault that is equally likely on the tenth start points at pure mechanical wear. You have already established temperature does not matter, which rules out a few things: adding the sitting-time observation costs you nothing and rules out a few more.

Write it down for a week. Diagnosing from memory is how people end up replacing three parts.

On the electricity, since you asked whether it is just expensive: roughly speaking, each extra degree colder costs a few percent more energy, so −25 against −18 is somewhere in the region of 15-25% of that appliance's consumption, depending on insulation and how often it is opened.

On a chest freezer, which is the efficient kind, that may be a small amount of money. It is still money for a quality difference you would struggle to detect in a blind test.

The counter-argument for keeping it cold: a chest freezer at −25 has more thermal margin during a power cut. Full, closed, and starting from −25, you get meaningfully longer before anything approaches −10 than you would starting from −18. If you lose power regularly, that is a real reason. If you do not, you are buying insurance you never claim.

The canister detail is the bit I did not have. So the advice is not wrong so much as fifty years out of date, which explains why it is stated so confidently: somebody's father was right about it.

If you would rather stay in the fridge, the compromise that gets you a few extra days is a proper airtight container plus a piece of kitchen paper on top, changed if it goes damp.

The paper is doing something specific: cheese gives off moisture but also dries at the surface, and what you want is a small humid buffer that is not condensation sitting on the shreds. Sealed tub with nothing in it goes slimy on top and dry underneath.

Still only buys you five or six days. The freezer is the answer if you want a week or more.