Steps to reproduce:
1) Create template with 2 dashboards.
2) add any widget to dashboard_1 and leave dashboard_2 empty (no widgets).
3) Link created template to host.
4) Navigate to Monitoring->Hosts->Dashboards (host with linked template).
5) In the top right corner switch dashboard from 1 to 2.
6) Try to switch the dashboard back from 2 to 1.

Result:

Expected:
It should be available to switch between dashboards.