Este es un problema de lagunas e islas. Un método para resolverlo usa row_number() :
select Date, User, min(Time) as start_time, max(time) as end_time,
Location,
listagg(Service, ',') within group (order by service),
count(*) as cnt
from (select t.*,
row_number() over (date order by time) as seqnum,
row_number() over (partition by user, date, location order by time) as seqnum_2
from t
) t
group by Date, User, Location, (seqnum - seqnum_2);
Es un poco complicado explicar cómo funciona esto. Mi sugerencia es ejecutar la subconsulta y verá cómo la diferencia de números de fila define los grupos que está buscando.
