@AndySoft If you're using hardware version 2 of that router, then the last firmware was released in 2015. You should maybe get something newer.

  @qazwsxedc16 
I think any router should be running as it is supposed to, independently of when it was built,

The company should keep the product running as expected and conform to specifications.

This erratic behavior has been so since I bought it, a friend of mine purchased version 3 of the hardware and has the same problems.

In my country, Argentina the resellers sold those products as brand new very few years ago.

I bought mine in 2019, not so long ago, the HW was still 4 years old, but when you buy, you expect something to run clean independently on the HW, if not they should withdraw it from the market ASAP, or in any case give support on failed/buggy HW.