Yes, this is related to your other post. Using eyetracker causes experiment slowdown/unresponsiveness - #2 by sol
Until this issue is fixed you need to start / stop recording when it is unlikely that a key press / release event that is needed will occur. For example by start recording right after calibration and ending recording at the end the block of trials instead of doing so at the start / end of each trial.
again, sorry for any inconvience.