Bug in textBounds method?

Hi,

Please see this p5.js sketch: https://editor.p5js.org/wimpo/sketches/gSt5JCJLG
I have figured out the letter ‘f’ causes the font.textBounds method to render incorrectly when using the IBM Plex font.
The top two boxes are weights of the font IBM Plex and the ‘f’ char seems to cause a new line.
The bottom two boxes are weights of Montserat and don’t suffer the ‘f’ problem.

Is anybody else seeing the same result? See attached screen grab.
Plex+Mont-screenshot