No idea if this is a real problem or not. I don't know what the little canisters are rated for. It does seem plausible though.
lol. Thanks for your vote of confidence.
Backpacking canisters are generally intended for a blend of gasses, typically propane with either butane or isobutane. When you blend gasses, the resultant mixture has a vapor pressure somewhere between the various vapor pressures of the constituent gasses.
Now, go look on line or in stores. You will find
no brand with more than 30% propane. A little flimsy (by comparison to 100% propane car camping canisters) backpacking canister just isn't built for 100% propane.
HJ