The FTDI virtual com port driver has two very important settings - latency timer and serial enumerator. If either of these are not set correctly the monitor will exhibit a significant delay in response to amp telemetry.
The first step in diagnosing such lags or delays is to verify these two parameters - even if you know you've already set them correctly. The reason is that Windows Updates - especially when FTDI driver updates are included, the installation of other virtual com port drivers and just system reboots have all caused these parameters to get set back to their default values.
Latency Timer: Must be 1 ms
Serial Enumerator: Must not be checked
To access these parameters, launch Device Manager and open the properties of your FTDI virtual com port. Click the Advanced button.