Interesting. Do you have a photo?

What kind of canister did you refill, what did you refill them with, and were you careful to only fill to their rated weight limit?

First, the most critical thing is to note how much a full canister weighs when you bring it home fresh from the store. When you refill, NEVER exceed this weight. Overfilling can lead to dangerous pressure levels inside the canister. If you forgot to weigh the canister when you brought it home, you could weigh an empty canister and add the net weight printed on the canister to derive your max weight, but I think weighing a fresh canister is the better option; it avoids any potential math errors.

Second, know what type of canister you're refilling. Is it a 100% butane canister? Is it a butane blend canister? Is it a 100% propane canister? Different canisters can accommodate different gasses, and you need to know which type you have.

Last, only refill with a gas or gas blend with a vapor pressure that is equal to or less than what originally came in your canister. Do NOT refill with a gas or gas blend with a higher vapor pressure. Generally, refilling with 100% butane is relatively safe (as safe as canister refilling gets anyway) because 100% butane will always have equal to or lower vapor pressure than any combination of the gasses typically used to fill canisters (butane, isobutane, and propane).

You can get some idea of what's going on with various blends by looking at the following chart:


Note that the above chart lists propane and butane only. Isobutane is not listed. Vapor pressures with isobutane will always be higher. So, that chart can give you some idea with propane and butane, but don't use that chart for isobutane. You'll need to look elsewhere for that information.

HJ