Inflation =! an increase in money supply.
Inflation = a decrease in the value of a currency which is caused by an increase of its quantity divided by market size.
When the market size is fixed (eg, 100% penetration of a fiat currency that is legal tender and required by law to be accepted by everyone in a nation) then any printing of new money causes inflation.

But with bitcoin while new coins are being created, the market size & the number of people participating is increasing much faster than new coins are minted and as a result bitcoin is experiencing deflation (value of money rising) despite new mining (as can be seen by the rapid rise of its value)