Undefined offset PHP notice

I have a large number of PHP notices being thrown on my forms pages with this plugin active. I confirmed we’re running the most recent version of this plugin (4.0.0) along with Gravity Forms 2.5.15 (which I believe is also the most recent version).

Notice: Undefined offset: 1 in \\SERVER\MYSITE\wp-content\plugins\gf-form-multicolumn\includes\public\WH_GF_Multicolumn_Public_Form_Current.php on line 90

This is repeated a number of times complaining about the offset of 1, then repeats a number of times for offset 2, all the way up to offset 6. In total I have 69 notices being thrown above the rendering of the form.

Line 90 appears to be
$divisor = ( $this->rowColumnArray[ $this->rowCounter ] > 0 ) ? $this->rowColumnArray[ $this->rowCounter ] : 1;

Thanks in advance for taking a look!