Incoming USB characters lost

I have an Arduino Pico connected to MATLAB and I use Terminated (CR/LF) trigger to read the input. Each message is about 10 to 12 characters and they come in at random intervals of a few seconds but potentially as fast as a few ms apart. It works 99% of the time or so but I am losing some character packets. It appears that if I am also writing data to disk that USB packets get dropped more often. Is there a way to make sure data isn't lost?

[Rik]

You might have to share more details about your setup and your code.

Also, does there seem to be a relation between the interval and the chance of data loss?

[Andrei]

Gavin, please contact MathWorks Support to investigate the issue.

[Gavin]

Although every line sent ends with CR/LF terminator. Later invertigation has shown that the string arrived and is sitting in the Serial port's input buffer. I did a work around where the Arduino Pico sends an extra CR/LF if it doesn't hear from ML in a while (a few seconds) indicating that it's hung up. So far that's working.