@Hank21 

I'm facing a similar issue.

I got two WANs with similar bandwidth and the R605 keeps sending way more (3-10 times more) traffic* through the second WAN port. Even after changing the bandwidth description in WAN setup.

Both are (in theory) 80Mbps/10Mbps. After I had seen this problem, changed the second WAN setup to lower download bandwidth (like 50Mbps) and nothing changed. It even increased the upload traffic, too, on WAN2.
One side note and I'm curious if it can effect the load balance algorithm:

these two connections are identical, except that WAN1 is configured with dynamic IP, the WAN2 with PPPoE.

And in the system log I see that WAN1 releases and then reassigns IP from the ISP every 5 minutes (they confirmed that it's their normal operational rule), while the WAN2 with PPPoE never does it, or at least it never appears in the logs.

*Or what is also possible is that the traffic statistics (in standalone mode) in R605 is buggy. It's quite likely, not only because the real time traffic statistics data is never even close the the real usage but also I experienced that when I used a device with a certain amount of traffic usage, the router didn't show that amount, not even close.

If I had two connections from two different ISPs, I could at least see in speedtest which one is given to that device but as both are from the same ISP, I can't check it.

In the past I had a less reliable LTE connection as WAN2 and it caused internet shortage, perhaps because the router had kept prioritizing the WAN2.

By the way, a partially related question:

What is the explanation in policy routing when Priority is chosen instead of Only?

How does it decide the likelihood, what is the meaning of Priority in this case?

(I don't use any policy routing at the moment, I'm just curious)

Hank21 wrote

It seems like you 1st modem(to WAN1) does not have a stable connection with your router, so the router keeps switching to WAN2. You may try connect the 1st modem to WAN2 and 2nd modem to WAN1 then test again.

  @Hank21 

I couldn't try changing the two connections for lack of oportunity to suspend the local network. However, there are some important thoughts:

- there was one unstable connection indeed. Just not the one connected to WAN1. The opposite. It was on WAN2 that shows about 10 times more traffic on downloads (not on uploads though). Later the provider repaired that connection on their side. And it continues to show multiple times more traffic via WAN2.

- after all of that, I resetted the statistics and in Policy Routing restricted my computer's IP to use WAN1. Then started to run speedtest multiple times.

Previously I realized that the statistics have some delay, so I waited 10-20 minutes (the delay should be just 10-20 seconds but I wanted to be sure), and it still showed some 20MB of downloads for the whole vlan where I was connected, not just my device.

It means, the statistics feature in R605 v1.1.1 is clearly buggy!

After that, I can't take it seriously, unfortunetely it doesn't represent what it is meant to.

In this case, it's possible that the load balancer works fine and just the statistics are false but that's not informative.