Gateway Network and Alarm in Shelving

I have two pair of gateway, each pair is in redundancy. I linked master of each couple with other through gateway network to share tags.
It work fine but when I query shelved alarm both system go in slowing and lost comunication with its clients and devices. To restore system I must reset connection between two master.
It’s systematical, each time I access to shelved alarms crash both gateway

Some idea on possible cause