TDMoIP on ePMP Force 200


We have a problem dealing with TDMoIP over ePMP Force 200. We builded scheme like this:
(E1)RAD Ipmux 2L(ETH) - ePMP Force 200 - ePMP Force 200 - (ETH)RAD Ipmux 2L(E1)

All Cambium devices are working in PTP mode and distance between two of them is about 2km. FW version: 3.3. There are 2 tagged vlans on RAD's ethernet ports (one for management, second for TDMoIP traffic). The problem is that synchronization between two RADs constantly falls and there is no OAM connection.
I thought that problem was in noized ether so I made test bench for that problem (distance about 30m, manually limited power on them and so on, but had new devices), but problems still remained. We decided to use Intracom devices (works in 70-80 GHz) and problem gone, but this is unpreferable decision due to expensiveness of Intracom devices.

Is there any way to avoid the loss of synchronization on Cambium devices?

Thanks in advance.

So first off, please update both radios to the newest 3.5.2 release and try your test again. If that still fails, what mode are you using TDD, TDD-PTP, or ePTP mode and have you tried them all? Do you know what kind of MTU this service requires? By default ePMP uses an ethernet MTU of 1500 bytes, but it can be increased to up to 1700. Lastly, have you checked the ePMP radios interfaces to see if there are any packet errors or packet drops on the ethernet interfaces?