Data loss issue in FTDI FT232H and FT2232H Sync 245 FIFO Mode (Part2)

Continuation of Part1

I searched and found several same data-loss case.
This trouble can see since early 2010's, and even now.
The data-loss causes every 500 data (my case is every 510).
And remaining data is correct.
Such as device like FT232H or FT2232H products in large quantitie., If it has bug, we must be lots of information.
But data-loss's information is a little.

Then I asked FTDI person about this case, and got reply as follow,
See TN_167 FTDI FIFO Basics.
The 245 FIFO permits to read only when TXE# is Low. If buffer is full, TXE# changes High and inhibits data input.
But some users report TXE# goes back to Low after a brief period.
This can resulet in data loss due to overrun.
To prevant this, use RTS_CTS flow control( this device have no RTS_CTS control pin, but this is effective).

I tried this, but no effect.

to be continue Part3.