From next week (from 15.03.2021), Bity will charge an additional fixed fee of 0.000045 BTC. This means: normal fee 3% (or 2.5% with referral code) + 0.000045 BTC.
As the Bitcoin network is currently very busy, the fees are correspondingly more expensive and Bity has to charge this fee to the customer.
This is only temporary (a few weeks possibly months). The implementation of Native Segwit, Lightning and other solutions is being worked on so that this fee can be waived again as soon as possible.