Peplink speedfusion traffic issue

I had have encountered the Speed Fusion VPN issue.

After I created the SpeedFusion between Device A & B with WAN1 Link, everything went well.

I monitored the Physical interface & VPN traffic with PRTG tools.

The WAN upload and download maximum speed is 20M/20M(Device A) & 15M/15M(Device B).
I found the traffic about WAN1 is well, but the VPN traffic is wired.

The PRTG shows that WAN1 traffic is in normal range(within 20M/20M), but the Speed Fusion VPN sometimes would exceed the traffic up to 100Mbps.


Device A:
Model: Peplink 580
Firmware: 6.3.1 build 1631
WAN1: Download: 20Mbps, Upload:20Mbps

Device B:
Model: Peplink 380
Firmware: 6.2.2 build 3362
WAN1: Download: 15Mbps, Upload:15Mbps

How could I fix this problem?

Please ensure you are using latest firmware version and MIB. We do have improvement on this.

MIB - http://download.peplink.com/manual/peplink_balance_snmp_mib-6.3.zip

Balance 580 - http://download.peplink.com/firmware/plb2500/fw-b305hw2_380hw6_580hw2_710hw3_1350hw2_2500-6.3.3-build1778.bin

Balance 380 - http://download.peplink.com/firmware/plb700/fw-b305_380_580_710_1350-6.3.3-build3560.bin