How to identify the cause of rx-too-long on MikroTik?

Question

network hardware

Good afternoon
There is a model 3011Ui (6.46.2) on hand, client traffic is received through the sfp port (~ 100-150 Mbps l2, cellular base station), flowing through the EoIP tunnel to another microtic. After connecting, the client began to complain about increased losses (previously, the junction was at a different address), which is strange, given the more powerful hardware and fewer hops to the output point, during the diagnostic process, I noticed that the value of the rx-too- parameter was growing quite quickly on the sfp port long (by about 1k/s), while L3 MTU 1700 and L2 MTU 4096 are set on the interface itself and the bridge. I tried to set the value higher, but the counter does not stop growing, the client also checked the traffic for its part and they say they don’t see anything like that . On the forum, I did not find any information on such a problem, in your opinion is this a bug or not? How else can you find the cause?

Answer 1

Apparently, this is some kind of another bug in the piece of iron, they stuck into the gap and put another microtic (960pgs), this counter does not grow.

Answer 2

https://wiki.mikrotik.com/wiki/Manual:Interface/Et...

rx-too-long (integer) Total count of received packets that were larger than the maximum packet size

Do you have larger packages?