Xiaomi AX3200 (mediatek/mt7622) + 22.03-SNAPSHOT + PPPoE: redial / hang-up problems

My ISP (DIGI) uses PPPoE with a weekly connect time.
They don't like multiple dial-ins, and responds with Too many sessions. And when the router don't hang up the connection properly, one should wait a few minutes to timeout the Too many sessions response.

Here is a log about my problem:

  1. PPPoE connection ends with Connect time expired
  2. router redials immediately and ISP accepts
  3. got a modem hangup with connection time 0.1 minutes
  4. subsequent redials fail until the Too many sessions times out at ISP
  5. after 6 minutes the router is able to create the pppoe-wan connection

A similar problem I could reproduce with a simple ifdown wan command:

  • the router redials the PPPoE connection
  • ISP denies with Too many sessions
  • wired access to router lost for a few seconds (:thinking:)
  • ISP accepts in a minute ... instead of 5+ minutes

What's going on?
Why the first redial terminates after a few bytes?
Why does start the router redialing even if I explicitly asked for ifdown wan?