It widely depends.

If a stablecoin is properly and fully backed by the "thing" it replaces - usually USD, then there should not be artificial inflation.

The problem starts when stablecoins are not baked. And here there are at least two problems: those using the not-backed stablecoin face themselves the risk of finding themselves holding a bag of coins with no value (for example many gold-pegged stablecoin projects were for example not backed and they're long gone), and yes, the other problem is that it can cause artificial inflation. Still, maybe the oldest stablecoin and surely the most well-known one, USDT, has a long history of not being properly backed, yet people still accept it and use it, helping the crypto market being (somewhat?) artificially inflated.

In theory, one should DYOR and avoid the fishy ones. Sadly, the reality shows that this doesn't happen.
The only good news seems to be that at least the newcomers in the stablecoins "market" seem to have proper backing (or at least most of them).