fldigi- after MT63 mode switch, first transmission is garbled, subsequent tx are fine

Hello,
    I would like to add some additional information to help troubleshoot. I'm running PowerSDR v2.7.2. 
The transmission remains garbled throughout the transmission of the entire initial message, no matter how long.
   From the garbled audio and spectral display, it appears as if the signal is low pass filtered 
to below 1/2 the original BW, sounds like samples are dropped, and is not successfully processed by any receiver.

   I  don't remember seeing this problem prior to about a year ago. My detailed settings are:
Audio:
Primary: buffer 2048; Sample Rate 96000
VAC1: Windows Driver WDM-KS; Buffer Size: 2048, Sample Rate 96000, Buffer Latency 0 ms

DSP Buffer Size:
Phone RX/TX: 256,256
CW: 2048
Digital RX/TX: 256.256

CAT: Enable CAT on Port COM17, 57600 Baud, Parity: none, Data: 8, Stop: 1
PTT: Enable PPT on Port COM 16, DTR, ID as PowerSDR

VAC Control Panel Settings:
2 Cables
Up to Auto Worker Threads
Prio: 24
Connected Line Source: Line

SR 11025...96000 BPS 8 ... 32 NC 1 ..2
Max Inst: 2, MS per int: 1, Stream fmt limit: Cable Range, Clock Corr Ratio: 100

Com0Com:  (CAT Port on Flex 17)
COM 7: emulate baud rate; COM 17: enable buffer overrun

Fldigi: User RigCAT
Rig Desc File: PowerSDR.xml; Device: COM7
Retries: 5, Retry Int (ms): 50
Write Delay (ms): 25l Init Delay (ms) 200
Baud Rate: 57600
Stopbits: 1

Toggle DRT for PTT
and Hardware PTT settings:
Device: COM6, User DTR


     respectfully,
    Eddie Jennings, AJ4OC, NNN0HBO/GBS




   

Thank you Andrew,
     I found a new manifestation of this problem- NOT in Fldigi, but in RMS Express. If the first transmission is garbled, then all subsequent transmissions are an no connection can be made.

    I then could simply exit RMS Express and try again, until the first transmission  is not garbled.
When it system works it works flawlessly, which is most of the time.

    Intermittently, I do run across long runs of failure.  I was able to connect and check traffic today.

   My Winmor WL2K settings are:
Radio Model: Flex radios
Antenna Selection: Default
USB Digital is checked
Radio Control Port: Serial COM7, Baud 57600
PTT Port: Serial COM6, Baud 57600, Enable DTR checked

    WINMOR TNC Setup
WINMOR Capture Device: Line 2 VAC-eb
WINMOR Playback: Line 1 VAC-df


   Any information is appreciated,
     respectfully,
     Eddie Jennings, NNN0HBO, AJ4OC

I just learned on a MARS net that another Flex 3000 owner is having the same problem using Windows 8 with both Fldigi and RMS Express. 

Any comments, hopefully more informative  than, subsequent outside flagging as "NOT A Problem" are appreciated. "NOT A Problem" is more palpable with a short e-mail or other communication, respectfully.

     respectfully,
    Eddie Jennings, AJ4OC, NNN0HBO/NNN0GBS