Whenever ue moves from idle to connected mode, ue resumes all bearers those were established before moving to idle mode. This happens as per 3gpp and can get more detail in 23.401 section 5.3.4 Service Request procedures.
When ue moves connected to idle mode on the basis of data inactivity timer expiry, in this case enb deletes ue context from enb and informs ue and core nw about ue context release. More detail can get in 36.331 and 36.413.