Hello,
I have the exact same problem and I have posted a thread here (before I found this thread).
I can confirm placing a 10/100 switch between the BT modem and the RB solves the issue but it shouldn’t be required. I would like an official response from Mikrotik. I am willing to provide whatever diagnostic info it takes to solve the issue. As an IT consultancy we have a lot of FTTC customers coming online and if Mikrotik can’t solve the issue we might as well stop using them. This is disappointing because I invested a lot of time learning about them and placed my trust in these devices. Now the boss is skeptical about my suggestion of using Mikrotik and their reliability. It looks bad on me and Mikrotik… I guess now is the time to prove you listen and respond to people’s concerns within a reasonable time frame. I have email support regarding this issue. The boss doesn’t wait around.
Awaiting your response with glee.