I'm experiencing whatsapp delay messages inside the ticket

Hi, we have Suite Professional plan and we have an active WhatsApp chanel.

I note a strange behavior in the Support ticket created from the WhatsApp chanel. This is the case:

I'm an administrator agent and i have solved a ticket from WhatsApp chanel so i change the ticket status from open to closed.

After a bit the end-user reopen the ticket by messaging into the same WhatsApp chat. So i see the notify:

but when i open the ticket i can't see the last message (Text of the message: "Test 12"):

I have tried to refresh Chrome also with the ctrl+F5 but i still can't see the last message.

I have find this work around to see the message without waiting every time 10-15 minutes: i change the ticket assignee from my agent to my group and apply the update status to the ticket, so finally i can see the last message:

Someone can help me to understand why this behavior to see the last message with Whatsapp channel?