High CRC error on modem

I have been using openwrt for about 2 years now, and since then I have had two problems with no explanations

  1. I have a PPPoE connection. sometimes I can't establish a new PPPoE when I lose connection for more than 3 minutes or so but to be fair I had a similar issue with opnsense and even some people have had this too with the same ISP I assume it's ISP issue but I am not 100% sure as literally any other router except openwrt and opnsense works just fine.

  2. the last issue I discovered by accident after I failed to fix the first issue. when my vdsl modem is in bridge mode the CRC errors skyrocket after a few hours (30K+ errors in less than a day). that led to very bad packet loss and very slow speeds. currently, I am using my vdsl as my main router and openwrt as an access point, and in more than 2 days I have had only 30 errors so far I tried 2 other modems to make sure. all 3 showed the same symptoms of high CRC errors in bridge mode

does anyone have an explanation for this, especially the last issue it's buzzing me out as CRC errors should be related to the modem how can bridge mode make a difference?

thanks.

Both issues sound like bugs in the VDSL modem. If you can provide your own, looking for a cheap replacement on the second hand markets may be useful (around here you might get decent devices for 5-20 EUR, at least if super-vectoring (up to 250/40 MBit/s, profile 35b) isn't required and normal vectoring (up to 100/400 MBit/s, profile 17b or less) is all you need).

as I mentioned I tried 3 routers/modems from 3 different brands. all showed the same symptoms

I think it's very unlikely that all 3 modems are defective in some way.

I am starting to doubt that it may be my NIC on the openwrt box, but I have swapped the wan and the Lan nics around, and yet still the same issue.