Tasks -> Restore -> Database... from Object Explorer in SSMS might not find a valid restore plan or might find one which is subopt
When a valid restore plan is not found, error "Unable to create restore plan due to break in the LSN chain" is raised. When a valid although suboptimal plan is found, no error is raised.
This will be addressed in the next major release of SSMS.
Fixed in SSMS 18 preview 5