After a few days of operation I measured a short circuit between GNDB and I/OB2.
I unsoldered the part and measured between the Pins and it's definetely the IC and not the board.
To simplify the evaluation I used the same power source for both sides of the Isolator.
Is it allowed to have GNDA and GNDB on the same supply?
The part was supplied from 2 different LDO's and both sides with 3.3V.
Is there any power supply sequence that could cause such a problem?