It must be a reaction to stress of some sort. Cold draught seems unlikely so too much dry heat? Is it in need of re-potting? A little fertiliser once or twice a year helps. You can tell by gently squeezing the leaves whether water is needed, firm & crisp they're okay, if they're softer like an overripe cucumber give them water. If they've got wrinkles they really need water but if you over water the leaves get brown, corky patches.
Given the weather lately a fortnightly drenching with, preferably, rain water would probably sort it out gradually. Occasional misting too.
I'm assuming you know how to make new plants from the fallen leaves?

Thank you, Darren. The leaves are firm and crisp. Just dropping off. Since I bought it from a cheap supermarket perhaps it was how it was stored there.
Yes, I did know how to make new plants, thank you and I’m trying. If successful does that mean I’ll get more money? :))

I had to trim mine when it got too big for the windowsill so had a dozen new ones. Still broke😄

Definitely a plant that is misnamed!

I always call them Jade Plants as they look like jade with the light behind them. Maybe need some feng shui mysticals in terms of positioning to make them an income source, I can't give the buggers away😄

You may not be able to give your plants away but you gave me a good laugh! Thank you, it was needed.