Hi ,
I can see that the device you are using is not listed among one of the validated devices mentioned in Azure docs (https://learn.microsoft.com/en-us/azure/vpn-gateway/vpn-gateway-about-vpn-devices)
My suggestion is to use the validated device to listed in the doc. It doesn't mean that the IPSec will not work on non-validated device. Since it is not validated and it is developed by a different vendor, we need extensive testing and troubleshooting to figure out the root cause.
I suspect this can be due to the rekey as this issue is not happening when the initial connection is established.
Regards,
Karthik Srinivas