AM1808 USB2.0 Device Communication Stop

Hi,

I'm using AM1808 as USB device(peripheral mode) and having a problem with USB2.0.

While USB communication is pending after the completion of enumueration, 
communication disconnect problem occurs.
By recovery of communication disconnect state, bus reset or enumeration are executed.
But the USB device won't be detected correctly(it is detected as unknown device).
This problem occurs so rarely. I'm trying to reappear the problem but not happening now.
So, I'm searching the following 

I'm searching for this problem including a possibility of the following errata.
And I have questions about this errata.

*AM1808 USB errata(advisory 2.3.1 USB0: Extraneous RESET Interrupt)
Q1.By what kind of condition does this errata occur? I want to know the details.

Q2.Once this errata occurs, how USB controller will act ?

Q3.There are workaround written in the errata sheet, 
   but I want the sample code. Is there any sample code?

Q4.Do you think there are relationship between this errata and the problem?

best regards,
g.f.