It is an interesting question.
To answer it you need to understand where the LPG comes from.
Energy companies get their fossil fuels from underground in the form of Gas ie Methane (C1- one carbon atom) with a bit of ethane in it (C2 – two carbon atoms) or Oil ie Propane (C3), Butane C4) and heavier molecular weights (C5 and above). Methane is the stuff that is piped from gas fields or chilled to form LNG and shipped in tankers. The C2 content has to be small for calorific value reasons. The Oil is sent to refineries where the C3/C4 is extracted and bottled for LPG with the higher carbon species then pushed through the refinery to generate as much cash as possible from fuels etc. The C2 stream is pretty useless and can only be used as a feedstock for Petrochems - so its pricing is handled differently.
Demand for methane is going up and up so you can see why the price is doubling and with Russian supply to go down, even more market pull. The world is theoretically awash with oil but pricing based on OPEC restrictions to production, so not allowing it go into the market – and now Russian oil not wanted by the west will increase prices of road fuel etc. Is the C3/C4 fraction in short supply? It's production will be linked to the processing of crude oil rather than production of C1's (methane) – and I guess a lot of the C3/C4 was coming from Russia along with the oil, so yes, likely the market will be short so prices going up. I doubt if a lot of methane usage can be replaced by C3/C4 but that could tip the balance in a 'short' market.
Pricing is all a big con! The people in need have to pay a lot more so drive the price up for everyone as the people with the fossil fuels make a huge killing. I'm nearly as right wing as Smelly but in this case an energy tax is essential.