What if the government of a country is irresponsible and issues a large amount of currency to buy Bitcoin?
Be responsible or irresponsible, be knowledgeable, experienced and skillful to manage their inflation or not, governments always lead their countries inflation. They can not stop it and it is how governments manage their national economies.
It is possible that governments use their fiat currencies to buy Bitcoin. So far we have yet known that who is (are) Satoshi Nakamoto? The founder of Bitcoin can be a person, a government or any entity.
No matter what the reason is, inflation is already very serious now. If some unscrupulous governments print a lot of money in order to repay debts and fight inflation, of course it will not be one time.
Two topics about inflation on Bitcointalk
Inflation and Deflation of Price and Money Supply[CHART] Bitcoin Inflation vs. TimeBitcoin Block Reward Halving Countdown