WinKFP flash of the PDC will not change the configuration, but it's good a start.
How did you code the E84 PDC from 8 sensors to 4 sensors? If you did this in ncsdummy manually then it's possible you have an invalid configuration as there are alot of 8/4 sensor options. An invalid config would likely cause strange or unexpected behaviour.
That said, I see no reason why default coding it with an appropriately configured E84.ssd shouldn't work. I have a program I wrote which should make this a little easier, I've also included a bundle of files for anyone brave enough to convert an E90 PDC to E84 as it's had some renewed interest recently. There's a dummy E84 ssd in there to get you started if you didn't have one already, as well as my own E84 PDC custom coded NETTODAT.TRC, though this is for a front and rear pdc E92 with an automatic transmission.
As far as I'm aware, the PDC doesn't care about what transmission you have. Deactivation is based on either how far you've travelled forward, or how fast you are travelling.
https://mega.nz/file/KU4hUKzY#wup7YP...n3rzctbj4xPafs
https://mega.nz/file/OJgRXSDA#IRW_ep...4e1rsbB6BUvXAM
For further troubleshooting, I would try disconnecting the TRSVC to eliminate the possibility of it interfering with the PDC on the CAN bus. An E84 PDC should still function even without it.