You have configured time types for collision, which is working as expected on the dektop. However, on the mobile app you recieve an error for same steps:
Error: "Request failed: You already have time off in period *** - ****. Please choose a different period"
Employee Central, Time Off
Employee Central, Mobile
Collision management for Mobile Time Off is not supported on Mobile (Andorid / iOs).
This is complex scenario and will be considered part of the long-term mobile roadmap (tentative b2105). No date has been confirmed as of yet.
Collision is not working on mobile, cannot request collision absence, Request failed: You already have time off in period , KBA , LOD-SF-EC-TIM , Time Off , LOD-SF-EC-MOB , Employee Central Mobile , Product Enhancement