Azure SQL Databases: High number of SA connections with "BRKR TASK" and "TASK MANAGER" commands
Those BKRK are related system processes and back end connections and do not count upon the limit of connections associated with every service tier. They can safely be ignored. BKRK processes are related to service broker on on-premises SQL Server instances and Azure SQL Database may be using it as part of the service it provides. 

With Azure SQL Database you will always see many connections and processes related to the automated features the PaaS provides to the customer. Learn more about back end connections here.

Instead of focus on system processes, please try to know if blocking is the culprit.

select r.session_id,r.blocking_session_id,r.wait_type,r.wait_time,r.wait_resource,r.total_elapsed_time,r.cpu_time,r.reads,r.writes,
s.nt_user_name,s.program_name,s.total_elapsed_time
from sys.dm_exec_requests r
join sys.dm_exec_sessions s
on s.session_id=r.session_id


Consider also deadlocks may be a possibility, and you can find them using below query.

select *
from sys.event_log
where event_type &lt;&gt; 'connection_successful' 
and start_time &gt;= CAST(FLOOR(CAST(getdate() AS float)) AS DATETIME)
order by start_time desc  -- event type = deadlock