Bug when passing string to Simple Text's text property via extendscript

Hi,

I have an issue with extendscript. Via extendscript I create a transparent video, put it on the track, apply the Simple Text effect and pass a string to the text property. The text renders fine, but when playing the video inside Premiere Pro or scrubbing the timeline, it adds random symbols after the text and it only does this when the text is set via extendscript. I attached a video example of the bug.

Any idea how to avoid this happening when setting the text in the Simple Text effect via extendscript?