Resolved! STM32 U575 LSE Clock doesn't start.
LSE clock is set in the Cube and initialisedAfter intitialisation the following registers are not set correctly and the LSE clock isn't calledRCC->BDCR->LSEDRIVE not set to hight event though macro calledRCC->BDCR->LSCOSEL set to LSIRCC->BDCR->LSCOEN...