Having issue with the STM32L552RC when configures and starts TIM for timebase instead of systick.

[BBeat]

Currently using the STM32l476 and changing to stml552 on existing board since needing more RAM. This occurs on STM32cube generated project with only RTOS enable and timebase set to TIM6.

[TDK]

How is the timebase source configured in the System Core -> SYS configuration?