Why does sum totals differ in query?

Question

with totals as (select two_sim_ind,
    case when account_type_key in(86,88,13,113,37,39,131) then 'B2C' else 'B2B' end as Segment,
    case when subs_activation_date_key >= time_key then 'New' else 'Old' end as Sales_to_active,
    time_key as TIME_KEY, name_region as REGION, area_name as DISTRICT, sim_type as USIM_FLAG,
    case when lte_device = 1 or lte_ind in('Yes') or lte_user > 0 then '4G Device' 
    when ind_3g in('Yes') and lte_ind in('No') then '3G Device' else '2G Device' end as device_tech_support,
    device_type as DEVICE_TYPE,
    case when device_type in('Smartphone') then 'Yes' else 'No' end as is_Smartphone_AAB,
    case when data_user in(0) then 'No' else 'Yes' end as is_Data_User,
    case when lte_user in(0) then 'No' else 'Yes' end as is_4G_Data_User,
    count(distinct subs_key) as A1M,
    sum(total_revenue) as REVENUE_TOTAL,
    sum(data_traffic_local_2g + data_traffic_local_3g+data_traffic_local_4g) as TRAFFIC_DATA_full_Sum,
    sum(data_traffic_local_2g + data_traffic_local_3g) as g2_g3_traffic,
    sum(data_traffic_local_4g) as Data_traffic_4g
from dwh.m as m
left join (select model_name, ind_3g, lte_ind
from dwh.w) as devices
on m.model_name = devices.model_name
where rtc_active_ind > 0 and subs_status_key in ('A', 'S') 
and (time_key >= '2021-12-01' and time_key <= '2021-12-01')
group by two_sim_ind, 
    case when account_type_key in(86,88,13,113,37,39,131) then 'B2C' else 'B2B' end, 
    case when subs_activation_date_key >= time_key then 'New' else 'Old' end,
    case when data_user in(0) then 'No' else 'Yes' end,
    case when lte_device = 1 or lte_ind in('Yes') or lte_user > 0 then '4G Device' 
    when ind_3g in('Yes') and lte_ind in('No') then '3G Device' else '2G Device' end,
    time_key, name_region, area_name, sim_type, device_type, lte_user)

select REGION, sum(REVENUE_TOTAL)
from totals
group by REGION

When I aggregate total of all records by region, value is significantly higher than it should be.

Result I get:

select name_region as REGION, sum(total_revenue)
from dwh.m
where (time_key >= '2021-12-01' and time_key <= '2021-12-01')
and rtc_active_ind > 0 and subs_status_key in ('A', 'S')
group by name_region;

Result of query and what I need:

Something happens to individual records when grouping by? What could be the reason?