Blocking upsert procedure
Since your spid 119 is in [sleeping] state, I'd recommend you to check:


DBCC Opentran() to check whether there is any open transaction on 119 (high possibility to my experience)
sp_lock 52 to check what lock in spid 52 is NOT granted
sp_lock 119 to check what lock it holds, and you can trace the lock back to the resource (such as table or index or key etc)


Also maybe you can turn on READ_COMMITTED_SNAPSHOT on your database to avoid the blocking between read and write operation.